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Full text of "73 Magazine (August 1989)"


AUGUST 1989 

ISSUE ff 347 

USA $2. 95 

CA^$3.95 

A WGE Publication 



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IC-4KL 



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ICOM^s all new IC4KL soOd state HF 
linear amplifier represents a hefty step 
forward in modem electronic technology 
and futuristic station design. 

ll installs in a limited sp; 
interconnects in a breeze and delivers band- 
commanding pefforrmnce in the most 
reliable top^)Hhe-lioe fashion. Give your 
signal a power boost with ICOM's IC4KL! 

GLOBE SPANNING POWER. 

The rugged IC4RL deliver 1000 watts 
output with full too percent duty cyck 




Covers 160-15 meters. A power boost that 
wiD be heard around the world! 

ALL SOUD STATE AND FUUY AUTOMATIC 

No lethal high voltages required No 
wami-up, no tune-up. no fumbles. FuHy 
automatic and overload-proieded Just 
mitch on and operate. Fallows band selections 
00 your ICOM transceiver. Add ICOM's 
optional EX^27 and setup even selects the 
proper antenna. Tbe ultimate HF amplifier! 

AUTOMATIC ANTENNA TUNER KUILT4N. 

Advanced design and wide impedance 
matching range, Iiitemal CPU stores pre- 
\TOus settings oo each band for rapid 
sinde-button operation, .'\utomatically 
seeks for and memorizes new settings 
if SWR changes or aniennas are swapped 




FUU CW BREAK-IN, 

The IC4KL us^ extremely quiet and 
high speed relays, A DX'ere winning edge 
aiw a racketeer's delight! 

UNIQUE MODERN DESIGN. 

Husk\ RP/PS unit rolls conveniently 
under desk or into nearby comer. All you see 
is a small remote oontrol featuring dual multi- 
Sanctioned meters for SWR and output w^atts. 

Tlie IC4K1 comes complete with a re- 
mote control unit, RF/PS deck and nine feet 
of interconnecting cable for easy installation. 
The IC4KL... Big Signal ftrfomiance backed 
by a one*year w arranty at any one of ICOM s 
four North .\merican Service Centers, 

Cm\mm Sennet MoHm {m 45*^7«19 

31 B0PiQn0DneSittl% km 1X73063 1777 PhoflmPikidy. Suit 201 

3071 ^asftsailiwt Wffloixi.flC vex2T4Ca;iala 

A!i stsled Sipedicalions aie suDieci lo chano^ wittirsul notice or odli^atiori An CiM 
radios s-grniipaniiy eKCeed FCC regijiaiii:>n5Tirn 



fimrting spuraus emissions ^KL689 



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ICOM 

First in Communicafions 



CIRCLE 354 OR READER SERVICE CARD 



NO OTHER FULL DUPLEX PATCH OR 

REPEATER CONTROLLER GIVES YOU 

SO MUCH FOR SO LITTLE 



FULL DUPLEX AUTOPATCH 
USING DUAL BAND 
RADIOS,.- 

Most people are within radio range of 
their base statioo 90% of the time. 

Why not fnstall an 8200 and enjoy your 
own private full duplex mobile 
telephone system? Only 3 

conndctions are required. The 8200 
provides both full duplex and half 
duplex operation. 

(Inquire about Private Patch V for 
simplex operation. Operates in 
enhanced sampling or VOX 

modes...user selectable.) 

ADVANCED AUTOPATCH 
FEATURES,-. 

The 8200 incorporates many features 
which are simply not available in any 
other product. For example... 

90 Phone Number Auto Dialer: The 
B200 will gtore (in non-volatile memory) 
90 phone numbers which can be dialed 
with abbreviated two digit key codes. 
The auto dialer is program mabie over 
the air or with the builtHn keyboard. 

Last Number Redial: Redialing the last 
number called is reduced to a single 
digit (plus access a)de). 

Hookflash: Operates call waiting etc. 
Simply press ' three times. Only CSI 
has it. 

Call Progress Tone Detection: Busy 
signals and second dial tones are 
detected and cause automatic 
disconnect. Ample time is allowed for 
dialing second dial tones when 
required. 

Powerful TotI Protection: One to four 
digit sequences can be restrk^ed. For 
example, you could tock out 0, 1, 976 
and 911. Additionally, digit counting 
will prevent dialing more than 10 digits, 
A separate 2 to 6 digit toll override 
code allows making toll calls when 
desired. Re-arm is automatic. 

Dial Access Remote Base: The 8200 
can be accessed and controlled from 
any telephone. Call up and drop into 
the system from your desk phone at 
lunch hour! 




PULLDUR.X3 



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-— f^ 



Ringout Selective Calling : Ordinary 
calls can be received using ringout 
(reverse patch) and mobiles can be 
selectively called using regenerated 
DTMF. 

Optional AN! access codes; This 
option will allow up to 50 separate 
(remotely programmable) 1 to 6 digit 
access codes. A call can only be 
disconnected with the code that 
initiated the call. Thus eliminating 
sabotage disconnects. 



AN ADVANCED REPEATER 
CONTROLLER... 

The 8200 is a powerful repeater 
building block and is perfect for all 
private and club systems. 

The 8200 contains everything 
necessary to convert any receiver and 
transmitter into a powerful repeater. 
Only one connection to the receiver 
and two to the transmitter are required. 

Menu style programming is 
accomplished with the built in keyboard 
and display. The user can select a 3 
digit repeater up/down code, CW ID 
message^ CW ID interval, hang time, 
activity timer time, and you can even 
select any Morse character as a 
courtesy beepll 

An optional plug-in CTCSS board 
converts the 8200 to private use. The 
incoming CTCSS is filtered out and 
replied with fully regenrated tone. 32 
tones are dip switch selectable. 



STANDARD FEATURES— 

• Line in use detection 
« 90 number auto dialer 

• Redial 

• Hookflash 

• User programmable CW ID 

« Regenerated tone/pulse dialing 

• Selectable activity, timeout and hang 

time timers 

• 3 digit repeater on/off code 

• Two remotely programmable 1-6 digit 

autopatch connect codes, (Regular 
and Toll Override) 

• Powerful toll protection 

• Remotely controllable relay (relay 

optional] 

• Ringout (reverse patch) 

• Busy channel ringout inhibit 

• Ring counting 

• Auto answer 

• Telephone remote base 

• DTMF-DTMF selective calling 

• Courtesy beep (any Morse character) 

• Automatic busy signal and dial tone 

disconnect 

• MOV lightning protectors 

• Non-volatile memory 
And MUCH morel 




CONNECT Systems Inc. 

2064 Eastnnan Ave. #113 

Ventura, CA 93003 

Phone (805) 642-7184 

FAX (805) 642-7271 



CIRCL£ 12 ON READER SERVICE CARD 




Dynamite 
Discovery 

Communicatiom Specialists' latest 
excavation brings to light yet another 
dynamite discovery— our new dip switch pro- 
granimable SD-1000. No need to tunnel your way 
through TWo-Tone Sequential decoding any- 
more, WeVe mined this amazing unit! Now, for 
the first time, vou can stock one unit that will 
decode all calls in a lOOCkrall paging system w ith 
±.2Hz crystal accurac>^ The EEPROM on- 
board memory can even be programmed for cus- 
tom tones, and every unit includes group calL 
Universal switched outputs control your call 
light, squelch gate and horn. The SD-lfVW can 



also generate CTCSS and decode 
TU^o-Tone Sequential. Its miniature 
size of 2.0'' X 1.25" x ,4" is no minor 
fact either, as itk a flawless companion 
for oui- PE-IUOO Paging Encoder We 
ensure one-day delivery and our one- 
year standard w^arranty T>ip the rich vein of 
Communications Specialists and unearth the 
SD-1000 or other fine gems. 




'■ " .i 



WS4 




COMMUNICATIONS SPECIALISTS, INC. 

426 West Taft Avenue • Orange. C A 92665-4296 
Local (714) 998^3021 * FAX (714) 974-3420 
Entire US,A, 1-8D0-854-0547 

CrRCL£ 10 ON RIADiR SERVICE CARD 



QRM 



Editoiiaf Off ii 
WGE Cefiler 
Hancocic HH 03449 
frfione 603-52S-4201 

Advertising Offices 

WGECemer 

HancocKNH 03449 

ptiQn^ ^00-225-5083 

OlrculatfonOfficei 

WGE Center 

Hancock NH 03449 

pfione : 603-52&4201 



ltehus€ripis 
Con'tntKJttofi& >n the lorm of manu- 
scrtpfs Willi drowtngs and/ur ptMsfo- 
graphs are weicomie and wtll he 
considered tor possfble ptibdcaiKXii 
Wa can assume rra rss^otnajbtiity tw 
loss Of damage to any matei'ial 
Plea^a Vficlose a stamped, self- 
addressed envelope wr^tti etch 
SiibiUFSAtO'Ti Pay^m^m for tiia i£S# of 
any unsoliciled matenal will be 
ftiad^ upon putilhCatbn, A pramium 
will be paid for accepted articles tliai 
havo been submitied electronic ally 
(CompuServe ppn 70310,775 or 
MCa Man "WGEPUe" or GEnie ad' 
dress "ZaMAG") or on disk as ar^ 
IBM compalible ASCI4 file Ypu can 
also cof^taci us at the 73 BBS al 
{603s 52&-4438, 3O0 or 1 200 baud, S 
data bits, no parity, one slop bit M\ 
contributions should be diracied lo 
ine 73 editor] at offices How to 
Write tot 73" guidelines are avail- 
able upon request US citn^ens must 
iricJiidfl the^r soclaj secunty numtHf 
with s^ubrrtctted manuscripts 



73 Amsteitr Radia fISSN OBQ^ 
S309) iS pubitstied monUi^ by WGE 
Publishing. Inc., WGE Cenier. 
FofesI Road, Hancock, New Hafnp- 
9hiTe D3449 Entire contents -'1989 
by WGE FobNs^mg, Inc. No part of 
thfs publication may be reproduced 
wllhout written permission from th© 
publj&her. For Subscription Ser^ 
vie as wrila 73 Ammeur Radio. PO 
Bom 58866. Boulder. CO 30322- 
8866, or call 1 -600-239 03&8 tn CO 
call 1-303^447 9330 TtiiB subscrip- 
tioji rale is: orta year $24.97: two 
years $39-97 Atftditional po^age for 
Canada a S7.00 and fm ottief for- 
eign counti'ie^, S19Q0 surface and 
S37 00 airmaiF p»er year Ali Uit&tQ/n 
or<Se^ must be accompanied by 
pofymAnt ts US funds Second dms 
postage pai<t ai Hancock. New 
Ham psiiire and at addttional mailing 
gl1iC«s Canadransecondciassmaji 
regtstratton numt>er 9566. Microtilm 
Edition — University Mscrofjlm, A/\r> 
Arbor. Ml 40106. Postmasier 9flnd 
address changes to 73 Amateur 
Radio, PO Box 5^866. Boulder. CO 
80322-8868. 



Con tract: 

Rftading this binds all you elec- 
fronikers Out there in Hamdom to 
perform ttte following: 

1) Send for our Writer's Gtiide 

2) Followtng instructions therein, ap- 
ply at leasi ooe of your braMcfiilds lo 
fjlin. papar. andl/ocdiskette^ 

3} Send ii 10 us in aitiete form so ttiat 
mm may pmU tt for evefyone's ben- 

No cavilling now — it you can de- 
sign in^Gf build It, you can w^lle 
about HI You'll feel better and you 
eveng^t pakj. 



AUGUST 1989 




AMATEUR 
RADIO 



Issue # 347 



TABLE OF CONTENTS 



FEATURES 

44 Find Your Signal the First Time! 

How to quickly deaJ with Doppler shift on the hamsats 

46 JEZ — JugendelektronJczentrum 

First-class ham education program 



AA6CQ/VE6 



HB9DU 



» ■> V « '^ 



HOME-BREW 

13 CTCSS, Fast and Cheap 

Simple PL lonc board project, * * - * . — ....... 

24 COCOA— A COIIinear COaxlal Array 

Deluxe 80m wire antenna* 

34 Control Your Rig from a PC 

This project lets your rig and home computer talk to each other. , 

42 Full-Wave VHFVertfcal Antenna 

Easy-to-build, good gain antenna * * * • 

48 Need FM? 

Add this mode to your rig at little cost 

49 lOGHzRFPreamp 
Gel started on putting together your 3cm ^iysrem! 

S3 IF Shfft, Cheap 

Quick 'n* cas> QRM-buster for your older rig. . , 



» - » * 



... N6UE 



W20ZH 



4 ^ b ft A * 



i ii-»fr«ft-il'^r JlJIT 1 



. , . AF8B 



**,.,,,, KB*^BQK 



. WB6IGP 



, WOWUZ 



REVIEWS 

18 Kantronlcs KAM 

Multi-mode controller with packet gateway function, PBBS, and much more! 

28 Ameritron AL-80A Linear Amp 

This reliable IkW amp won't drive you to the poorhouse. 

32 Ramsey COIVI-3 

Quality service monitor at Sess than one-third the cost of its peers. 

38 Ramsey SR-1 Receiver Kit 

SW liiicning and home-brewing fun for only S25. 



+ « 4 4 * t • 



■ *-«** 



. WB6RQN 



...WIFYR 



WB9RRT 



. WA9PYH 



BOOK REVIEWS 



31 Uno, Dos, Cuatro 

Introduction to the ^'^numbcrs" stations . , , 



# * A ■■ L 



W%1 OY 



DEPARTMENTS 



feedback... 
feehback: 

iVs like being ihcrt— 
right here muur offices! 

of our FEEDBACK canf 
oopege 17, Ytw'II TKiCkc 
& feedback min^ber at 
the bcgifminf cif each 
irtkk and cofumn. Wc^d 
til^ you In rmtc vrhal you 
read m* ttui v^ cah print 
Uffaat types of liitftgs y oa 
like best. And ihcn «e 
Vrjll draw otK Feetlback 
cafd each mcmth for a 
freesubscrtfHionMi 7J, 



80 Ad Index 

76 Abdvu iind Beyond 

55 Aerjsil View 

65 Xsk KubtMim 

94 Barter N' Buy 

58 Circuits 

92 Denhr Directory 
17 Feedback Index 
90 Ham Help 

17 Ham Profilei 
64 Hamsats 
62 Homing In 

93 Index: 8/89 



81 Letters 

66 ].4M>kirig West 
H Never Say Die 
70 New Products 
95 Propagation 
72 QRP 
lOQRX 
60 RTn' L4iop 
84 73 Intematkinai 
74 Special Events 

82 Tech Tips 
90 Updates 

6 Welcome Newcomers 




Cover of Ramsey COM-3 service monitor 
by Marilyn Moran 



Sm our nevy department 'Ham Pfo- 
nies" for more on Diane KG5CS 



73 Amateur Radio * August, 1989 3 





m 



o 



E[E\W/i\BB 









1 





, 







For a limited time Alinco Electronics will give a $100.00 "^Reward" for your working, 2 meter or 70 
centimeter Mobile Transceiver^ or $50.00 for your working 2 meter or 70 centimeter Hand-Held 

Transceiver, 

The way it works is really quite simple. Just take or send your old, but working, transceiver to your favorite 
deafer for TRADE-IN. Whatever the dealer offers for Trade-in allowance, Alinco will increase the amount 
by either $50.00 or $100.00, depending on whether it's a Hand-Held or Mobile, ON THE SPOT! 
There are only two requirements: 

1) The Trade-In ^* Reward" can only be used towards an Alinco DR-SIOT Dual Band Mobile or an Atinco 
DJ-500T Dual Band Hand-Held, on a Mobile for Mobile and Hand-Held for Hand-Held basis. 

2) The Trade-in unit must be in good working order and salable. 

Remember, the company that already gives you the best value for your dollar, and a two year factory 
warranty, now gives you something else that no other company does— A substantial Trade-in *' Reward" 
for using our products! ***OFFER GOOD AT TIME OF SALE ONLY. OFFER EXPIRES AUGUST 31, 1989*** 



AUNCO ELECTRONICS INC. 



CnCtf 67 ON HEADER SERVICE CARD 




ALINCO ELECTRONICS INC 

a 

20705 S- Western Ave., Suite 104, Torrance, CA 90501 • t213) 618- 8616 • FAX (213) 618-8758 



BIG POWER IN A SMALL PACKAGE 



DR- 510T 



DUAL BANDER 




The Tiny, Tough and Terrific Alinco DR-SIOT, 2m/70 cm IM Dual Band Mobile 
Transceiver has been specially designed to condense maximum performance and 
operating convenience into an ultra compact package. An impressive array of 
features give maximum flexibility in mobile installations, 



¥ 144.00 IVIhz^147.995 Mhz & 440-^450 Mhz* 
* CROSS BAND REPEATER FUNCTION 
^ BUILT4N DUPLEXER 



► CROSS BAND FULL DUPLEX 

► ENCODE/DECODE SUBAUDIBLE TONES 

► COMPACT SIZE: 5 Va" (WJ x 2" (H) x 8 Via" (DJ 



^ HIGH OUTPUT POWER : High: 45 Watts VHF, 35 Watts UHF^ Low: 5 Watts both Bands. 

• 14 Multi Function Memory Channels ♦ Multl Color LCD 



• 6 Channel Spacing Steps 

• 4 Scanning Modes 

• 16 Button DTMF Microphone 



3 Mode Priority Scan 

1 Call Channel 

All Function Keys lllumtnated 




* CAP and MARS Frequency Modifiable (Pernnit required) 

("2 -Year Limited Factory WarranlyJ) 



DR-ilOT 

2in FM Mobile TranBceiver 

# 144.00- 14Z995 Mhz ^ 

# 5 Va" (Wi X t Va* (H) X 6 73" {WJ 

# 45 WattsHi/SWatBLow 



DR-410T Coming Soon 

m 70 an FM Mobile Transceiver 

• 440-^450 Mhz 

m 35 Watts Hi / S Watts Low 



tCmtMfcmtm required) 



CIRCU 67 ON ftEAOER SERVICE CAUO 



Number 1 on your FeMback card 



Welcome, Newcomers! 



The Universe Electric 

In 640 B.C. Thales, a Greek philosopher, 
theorized thai elect rid ly wu!^ the soul in matter. 
Today we describe elcciricky as the flow of 
eiecirons. The electric chargi? is inherent in all 
matter, and when the positive -negative balance 
is disturbed, a net chsirge is created. Like 
charges repel each other and unlike charge^i at- 
tract each other. Vou can see the effects of clec- 
iTDStatic repulsion inctean, newly combed hair. 

Displays of electrical activity* such as light- 
ning, have always fascinated philosophers, sci- 
entists, and children. Do vou remember, as a 
child, rubbing your blanket in the dark to see the 
sparks fly. or making a balloon Ktick to the wall? 
Warnings to stay away from the AC outlet? Did 
that peak your curiosity? Something really 
amazing must be inside there for Mom to get so 
excited when you try to explore it with a fork* 

Phosphene^. those bright spots which appear 
befofie your eyas whenever there is a lack of 
external stimuli, can be induced by an electro- 
static generator. In the tSih century, phc^phene 
parties were popular, and Benjamin Franklin, 
kite-flyer and statesman^ took part in at least 
one. People would sit in a circle and hold hands, 
letting theniKelvcs be shocked by an electrostatic 
generator. Each time the circle (circuit?) was 
opened or closed, they would see phosphcnes. 
(Scientists still do not know exactly what pho- 
sphenes are, or how electrical stimutation or 
lack of stimulation produces them, ) 

.\ I easu r i ng E lectricity 

In 1751 Benjamin Franklin published Experi- 
ments and Observations on Electricity, which 
became ihe standard for electrical research for 
more than a generation. Since he left school at 
age 10, the work was entirely nonmaihematicaU 
but il inspired a French engineer, Charles 
Coulomb* to perfect a contraption called the 
"'torsion balance/' Experimeming with it, in 
1789 he discovered the law of electrical force 
and proved that electricity obeys an inverse 
square law. 

The inverse square law describes a relation- 
ship in which, under certain conditions, the in* 
tensity tifa spherical wave varies inversely with 
ihc square of its distance from the source. Now 
measurabte« electriefty could be studied scicntif* 
ically. 

Named after the man, one cuulomb is equal to 
the charge on 6, 280.000.000*000.000,000 elec- 
trons « or in scientific notation * 6.28 x 10**, 
When one coulomb of electrons moves past a 
fixed pt^int in one second, we say the current is I 
amp<!re. The ampere, or amp, named after 
Andre Marie Ampere, is the unit we use lo de- 
scribe tlie amount of currem- In 73 features, 
you'll see these abbreviations: A or amp, for 
ampere; niA. milliampere (0.00 1 of an am- 
pere); and mAh, milltamp hour(s). The last unit 
describes the amount of current flowing past a 
point for a given amount of time. 

In mathematical expressions, the current is 
represented by the letter I, for mtensity. This is 
the first of the three most important electrical 

6 73 Amateur Radio * August. 1989 



quantities alt hams should be familiar with. 

Although very old devices which may have 
been voltage cells have been found in unlikely 
places* we credit Count Volla, an Italian, with 
making the first batter^' in 1 796. He was the first 
to describe voltage, or electrical potential. 
Voltage is the amount of work done in moving a 
unit charge from one point to another againsi ihe 
electric field. Often compared to the water pres- 
sure in a pipe, it's the electric potential differ- 
ence between two points; there is an excess of 
electrons at one point, and a deficiency of elec- 
trons at the other point. The universe being the 
way it is* the free electrons will rush in to fill in 
the gaps. 

Mathematically, voltage is represented by the 
letter E, for electromotive force or EMF, or by 
the letter V for volts* the units of voltage. One 
volt across lO of resistance causes a current 
flow of I ampere. Voltage b another of the three 
important electrical quantities. 

The third electrical quantity, the unit of the 
measurement of resistance, is the ohm, svmbol* 
izedby the Greek letter Q. Mathematically* it's 
represented by die letter R* One ohm is iJie 
amount of resistance which will limit the current 
to one ampere when one voU is applied across 
the circuit. 

In the early 19th century in Germany, Georg 
Ohm discovered that a current in a circuit is 
directly proportional to the electric pressure and 
inverse I v to the resistance of the conductors. Wc 
call this Ohm's Law. Mathematically. it*s ex- 
pressed as E=IR. If you know any two of these 
quantities, its easy to find the third. You can 
transpose the terms to solve for either current or 
resistance; I=E/R and R = E/I. The watt, 
product of the voltage and the current (IV or IE), 
is the unit of electrical power. In formulas, it*s 
represented by the letter W. Fractions of the 
watt* ^uch as mW (milliwatt* or 0.001 watts) 
and mW (microwatt, or O.OOOOOl watts) express 
low power. For larger power levels, we have 
kW (kilowatt, or 1000 wattsj and MVV 
(megawatt* or 1 ,0(X),000 watts). You will also 
see ^li (watt hour) and kWh (kilowatt hour). 
These last two represent the amount of power 
expended continuously for a given amount of 
time (one hour). 

Electron Matters 

Electricity is a highly versatile form of energy 
in both its static and dynamic forms. Materials 
such as copper, gold, silver, lead, and many 
other metals, which are composed of atoms 
which have less than four electrons in their outer 
shells* tend to be conductors because they are 
electrically uastable. They lose electrons easily. 
and these free electrons make the electric cur- 
rent possible. 

In an electric current, a free electron doesn't 
travel from one end of the circuit to the other. 
Each electron only travels a short distance be* 
fore colliding with another atom* kniKking off 
more electrons* which in turn collide with other 
atoms. 

Materials composed of atoms which have 



more than four outer shell, or valence, electrons 
tend to be msulators, or poor conductors, be- 
cause they are electrically stabler. They hold 
onto their electrons and grab free electrons lo till 
in their outer rings (eight valence electrons* a 
full shell, gives complete electrical siabtliiy)* 
Some insulators are wood, plastic, and glass. 

An clement with four valence electrons in its 
atoms, stich as germanium and silicon* are gen- 
erally semiconductors. They are neither go^xl 
conductors nor good tnsulaiors. 

An atom which has the same number of orbit- 
ing electrons as it has protons in the nucleus, is 
electrically balanced orneuinil. A negative ion 
has a surfeit of electrons; it is negatively 
charged. An atom which has lost electrons is 
called a positive lon« or cation; tt is charged 
positively. Positively charged particles, such as 
holes in solid state electronics, can also prtxluce 
an electric current. 

DC and AC 

IX^ (direct current) is a constant-value electri- 

cal current that flows in only one direction. The 
amplitude, or strength, remains ai a constant 
level. 

AC (alternating current) is a flow of electrici- 
ty that constantly changes in magnitude and 
polarity. Magnitude refers to /FOw/nuc/i current 
is flowing, and polarity to the dipsctian of the 
flow, positive or negative, through the circuit. 
An AC wave rises from zero lo maximum 
vol^e in one direction* decreases to xcra* re* 
verses itself and reaches the maximum in the 
opposite direction, and decreases to zero again. 
This is one cycle of an AC wave. A basic AC 
wave is called a sine wave; it moves sinuously, 
like a snake. 

The number of cycles per second, or cps, is 
the frequency of the current. One cycle per 
second is one Hertz, or Hz^ named after Hein- 
rich R. Hcrt^, who showed that electromagnetic 
waves propagate in the same way as light wa%^es. 

Radio frequency wave^, which are AC waves, 
begin at 20*000 H/. (20 kH2j* and go above 300 
billion Hz (300 GHz). Since this range is vast, 
for convenience we use the standard metric pre- 
fixes with Hertz: kilo (1,000). mega 
(1,000,000). and giga (1,(X)0. 000,000). Thirty 
kilohertz, for example, is 30.000 Hertz* Com- 
bined with Hertz, these arc abbreviated kHz, 
MHz, and GHz. Frequencies below* 20 kHz are 
called audio frequencies* 

Harnessing Electricity 

Electricity is not a solid, a liquid, or a gas. Is it 
the soul in matter* the flow of charged panicles, 
or both? How will we describe electricity fifty 
years from now? 

When you turn on your ( ransceiver (transmit- 
ter/receiver)* you're harnessing one of the basic 
energies of the universe. By understanding the 
propenies of electricity, developing a system to 
measure it, and providing the hardware to chan- 
nel it, you can use it to communicate with people 
all over the world. And that's no small accom- 
plishment. . . . de Linda Reneau 



While others offer you some digital modes 
using 3 year old technology, only MFJ 
gives you all 9 digital modes and keeps on 



bringing you state-of-the-art advances 



MFJ-1278 

279 



95 




No three year old Lechnology ai MFJf 
Using I he laeesl advances. MFJ brings 
you 9 exciting digital modes and keeps on 
bringing j'ou sEaie-of-ihe-an advances. 

Ton get tans of features other mulii- 
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Only MFJ gives yau all 9 modes 

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Yon can t get all 9 modes in any other 
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you modes ihe MFJ-1278 doesn't have. 

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Extensive tests In Packet Radio 
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MFJ*s unequaled tuning Indicator makes 
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So now you can send your own high 
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Nwfnber 2 an your Feedback card 



Never sa y die 



Wayne Green W2NSD/1 





TAFF 



PUBU5HER/EDIT0R 
V^^ayn© Green WSNSDn 



EDITOR IN CHIEF 
Bryan Hsstir^gsKStS 

MANAGJNGEOfTOft 

HopeCurri«r 

SENJOR EDITOR 
Un&A Reneau 

INTERNATIONAL EDITOR 
Rtchard Phenm 

EDITORIAL ASSISTANT 
Joyce SawtelJe 



Are You Fighting Change? 

Whenever t run ifilo a staunch Morse 
CcMJe supporter, I can'l help but marvel 
ai how out of touch many hams afe with 
the changes techr^ology has made, not 
jiist in amateur radio, but the whole 
world, frrdeed, it is this inability lo cope 
with changes which is helping to sink 
our country economically, Thts isn't a 
vague phrlosophieaJ problem, it's one 
which IS having a major impact right 
now on youf ability lo make a living arvd 
is going, even more, io char>ge thirvgs 
enormously for your chtldrfin and 
grandchildren. 

Just a generation ago we imported 
only a small percentage of the things 
we buy, Indeed^ tiie term "imported" 
was quite a cachet which meant "un* 
usual . ' * Toda y it 's gett ir^g so al most e v- 
erything is imported. How'd that come 
about and what's it mean? 

Techrwlogy is whal happened. To- 
day's low-cost transportatton and com- 
muni cations has made tt possible for 
Ihe steel worker in Korea to he in difect 
competition with the steel worKer in 
Pittsburgh — for the car assembler in 
Japan to be in direct competition with 
the worker io Detroit. A general ior^ ago 
the costs of Iranspodation ar^J commu* 
ntcatrons added so much to prices that 
direct foreign compel itton was difficult 
and imports tended 10 be specialty 
items. 



Farm and Factory 

Look at the changes technology has 
made in farniing. When I was young, 
half of the American people were f arm* 
ers- Then came improved transporta* 
tion, such as raitroad rafrigefated cars 
and trucks, making It possible to sell 
farm products anywhere in the entire 
country instead of just locally. This in- 
evitably brou9ht on farm automation 
and I ruck fartns. Now we call 11 
agn business — and we see smaJi farm- 
ers ftghiing a tosing battle Today, un- 
der 2% of ouf popytation are larmers. 

Unless our unions recognize what's 
happened and make it possible for our 
factories to compete on a more equi- 
table basis with foreign producers, 
we're going to keep losing jobs, The 
last I heard « our car unions had. with 
the backing of the government, forced 
car makers to pay roughly double the 
average American wage to their mem- 
bers — and they've lost over 200.000 
jobs in recent yaafs^ Is tt any wonder 
America has been losing more and 
more business to imports? Even if their 
cars were made as carelessly as ours. 
they'd still be able to undersoil us. 

What about automation, you ask? 
Fine, Ihat cuts assembly costs, but we 
have to go some way to out-automate 
our foreign competitors. Korea may 
have low wages compared lo us. but 
some ot their electronic factories tve 



TURKEY 



ZONE: 20 




ISTANBUL" EUROPE 




QSL OF THE MONTH 

To enter your QSL, mail it in an envelope to 73, WGE Center, Forest 
Road, Hancock, NH 03449, Attn: QSL of the Month. Winners receive a 
one-year subscription (or extension) to 73, E retries not in envelopes 
cannot be accepted. 

8 73 Amateur Radio • August, 1989 



visited are way ahead of anything I've 
sean in the US in automatfon-— and I 
get around. 

Prohibitions and Resiriclions 
Don't Work 

This is a very basic problem— on© 
which trying to set up import restric- 
tions isn't going to solve— indeed, will 
only make worse. Trying io get us lo 
'Buy American" isn't going to work, 
eithef , Few Americans are going to put 
up with poor quality and higher prices, 
That ti just buikl a btack market. Name 
one product people really want wh^ch 
laws have been able to keep out. 

They fried it with liquor and the black 
market that developed laid the founda- 
tions for today's tax-free organized 
en me industry They tr^ed it with drugs, 
only to make crime an even big^r 
t>usmess. Recentty they tried it with IC 
chips, which quickly began pouring in 
via Canada to fill the rteed. 

If we can no longer compete wilh 
countries who have lower wages on 
mass produced products^ how are we 
going lo stay in business? America's 
industrial strength was built on blue^ 
collar mass production and now we're 
losing that edge— permanently. We 
can't untnveni jumbo jeis, coitiainer- 
ized shipping, and the who?e trucking 
industry. 

The weakening of our large firms can 
be seen in their gradual shrinking— the 
layoffs at the automobile firms, layoffs 
at steel firms (half the workers have 
been Eaid off so far). The only growth in 
jobs we've had m the Bast few years has 
been m s/nati business Perhaps it's 
time to start investing more in this 
growth market. 

Investing in Smalt Susiness 

Japan, Inc., may be able to raise 
Cain with our car market, and the 
Philippines with our shoes, but when it 
comes to short-run special products, 
they can't compete with our thousands 
of smati companies. Unfortunately 
there seems to be vrrtually no recogni- 
tion of thts major change in the econo- 
my, so our ta^t laws still are torcing as 
much prcKJuction overseas as possi- 
ble. Indeed, if we had as a basic gov- 
ernment policy the dest ruction ot our 
small manufacturing businesses we 
could hardly be more effective. 

CQntifJued On page BS 



ART DIRECTOR 

JAPANESE TRANSLATOft 
Daviid Co¥^>g WAILBF" 

ASSOCJATESrfECH ADVlSORV 

COMMITTEE 

MikeBryceWBBVGE 

Michael GeierKBIUM 

Jim Gray W1XU 

ChLicK Houghlon WB6IQP 

Dr Marc Leavey WA3AJR 

Andy M0cAUtstef WASZIB 

ioeMoeinciOV 

B« P^temaR WA6ITF 

Mik»SloneW3aCX:o 

Arti&s Thompson W7XU 



AOVERTtSlNG 
1 '603-525-4201 
1-SO0-225-50fl3 

SAIES MANAGER 

Ei^ Vefbin 

AOVERTISIHG SALES 
Jiffi Bait KAITQA 

AD VERTISIWS SALES 

COORDINATOR 

Lisa Niemeia 

MARKETING ASSISTANT 

Donna DiRussci 



WGE PUBLISHING, 
INC. 

CHtEF FtN ANCtAL OFFICER 
TtmPeitey 

CIRCULATION PIRCCTOR 
Bodn>ey Betl 

T V P ESETTING^P AG JK ATION 

Susan Atler>, Linda Draw, 

RuihBenedk:i 

GRAPHICS SERVICES 
D>te WilUams. Pen Actenft 

GRAPHrCS PHOTOGRAPHER 
DanCroteau 



dfttonal OfficM 

WGE Ceni&r 

Peiertorough, NH 034S8-1 194 

603-5a5'4201 

Subacrlptlon Customer Servke 

1-800.525-0643 

Colorado/i^oreiHgn Sub«crtb«rs 

caH l-aoa-M? 9^30 



Wayfi^ Gra«n Emsfprises is a diviaiCKi 
of IntomatKHial Data Group. 

Reprtnts: m« fjrst copy ot an arli^ 

de— $3.00 (each addithona] copy— 

SI .50) Wr!l3 to 73 Amateur Radio 

Magazine, WGE Center, Fores I Rciad, 

Hancock, NH 03449. 






. . . pacesetter in Amateur Radio 






Rated 




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TS-940S-the standard of 
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Pushmg thestate-ol-the-art 
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glow with superlatives, and 
the field-proven performance 
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^The Number One Rated HF 
Transceiverr 

• 100% duty cycfe transmitter 

Kenwood specifies transmit duty 
cycle ttme. TheTS-940S is guar- 
anteed to operate at full power 
output lor penods exceeding 
one hour (14.250 MHz, CW, 110 
watts.) Perfect for RTTY SSTV. 
and other long-duration modes 

• First with a full one-year 
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• Extremely stabfe phase lock- 
ed loop (PLL) VFO, Reference 
frequency accuracy rs measured 
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1 




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icmr^ 




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TUNE 




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SSB SLOPb rUNE 







AF tyn« operation 

•The Af TUME function feduces 
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• This tuncticin should omy be u^ed 
during Qperattor^ \n tfte CVV mode 



4. 



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^cw> 










I 



1) CWVariat^leBafijImdth Tuning, Vary the 3) SSfi SFape Tuning. Operating in the LSBsF^d 

passband w^dth cDnimuDUsly in the tlWJSIC. USB madss. triis iwni pafitl sontrol allows 

3fid hU modes, without aflecting \he center indepenifsnLcontinuauslyvafiableadiust' 

trefiuency. This effectively minimtzes ARM meni of f^ef^igli or low frequency sEopesDJ the 

If om nearby SSB and CW signals. )F passbsnd. Ttie LCD sutt dispJay illustrates 

2)AFTune.Enabladwft?ithepushotabuttan. the filtering position, 

thi!^ CW interference tight&r inserts a tun- 4) IF Noicti RIter, Tha tunable notch filter 

ablejhree pole active fiiterbstweantheSSB/ sharply attenuates interfering signals by as 

CWbEmodulator and the aubio amplifier Dur- much as 40 liB. As shown here/ttie interfering 

ing CW QSOs. this control can hn used to signal Is reduced, while the desired signal 

feducf jntertefing signals and naise, and remains ynaftectedTfie notch filter works In 

peahs audio frequency rtsponse tor Dpiimum all modes except FM. 
CWperfQfmance 



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' i -ji - 



« Complete all band, all mode 
transceiver with general 
coverage receiver. Receiver 
covers 150 kHz-30 MH2. Alt 
modes built-m : AM. FM. CW FSK, 
LSB, USB. 

• Superb, human engineered 
front panel layout for the 
DX-minded or contesting 
ham. Large fluorescent tube 
main display with dimmer; direct 
keyboard input of frequency; 
flywfieel type main tuning knob 
witfi optical encoder mechanism 
all combine to make theTS-940S 
a joy to operate 

• One-touch frequency check 
(T-F SET) during split 
operations, 

• Unique LCD sub display indi- 
cates VFO, graphic indication 
of VBT and SSB Slope tunmg, 
and time. 

• Simple one step mode chang- 
ing wfth CW announcement. 

• Other vital operatmg tunc* 
tions. Selectable semi or full 
break- in CW (QSK). RIT/XfT all 
mode squelch^ RF attenuator, filter 
select switch, selectable AGC, 
CW variable pitch control, speech 
processor, and RF power output 
control, programmable band 
scan or 40 channel memory scan. 



Optional accessories: 

• AT-940 full range (160-IOm) automatic 
antenna tuner* SP-940 external speaker 
wElh audio filtering • YG-455C-1 (500 Hz), 
YG'455CN^1 (250 Hz). YK-a8C-1 (500 Hz) CW 
(liters: YK-88A-1 (6 kHz) AM filter • VS-i voice 
synthesizer • SO-t temperature compensated 

Oympieres&^ice manuais Bfe avatlablB for ali Kenwood iranscetvers and mo& accessories 
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€iystB\ oscillator • MC-43S UP/DOWN hand 
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station mics.» PC-1A phone patch • TL-922A 

linear amplifier* SM-220 station monitor 
• BS-8 pan display • lF-232C/iF'10B 
computer interface. 



KENWOOD 

KENWOOD U.S.A, CORPORATION 
2201 E. Domjnguez St., Long Beach. CA 90810 
RO. Box 22745, Long Beach. CA 90801-5745 



QRX. . 



Nuinber 3 on your Feedback card 



H^fTBD BY BRYAN HASTINGS NS IB 



WB6N0A Industry 
Service Report 



Ever wanted to throw a bouquet or m 
brickbat at a service department of an ama* 
teur radio equipment manufacturer? Now'd 
your chancel 

Gordon West WB6N0A. noted ham educa- 
tor and prolific author of a wide range of ama- 
teur radio related articles, has embar1<ed on 
an industry service study, to appear in print in 
^e first half of 1 990. As part of his study. West 
will visit the US divisions of major amateur 
radio equipment manufacturers, and inter- 
view the heads of the service departments at 
each company. West will also outline in his 
report what hams can do on their part to 
achieve smoother and more efficient service^ 

The most important part of his report, how- 
ever. wHI be YOUR input. Send a self-ad- 
dressed envelope to Gordon West to obtain 
the service survey. He wants fo hear from 
anyone who feels they have something impor- 
tant to say about their dealings with these 
service departments. Was customer support 
prompt and courteous? Were equipment 
repairs turned around quickly? Which conv 
panies have given you good service? Bad 
service? 

Please send your SAE, dated no later than 
November 30, t989, to: Gordon West 
weefslOA, 2414 College Rd-, Cosla Mesa, CA 
92626. ATTN: Service Survey. You may aJso 
download the survey form from the 73 BBS 
(see connect info below^ in 'Thanks*'), from 
the/73magSIG. 



id 



I Hear You" 



Our spologfes to Debra Davb N7IHY, the 

curator of the ATV mobile station on (he cov- 
er of the July MicrowaveA/ideo issue. The cov- 
er credit incorrectly listed her call as KA7FPL 
Deb has been in the amateur radio industry 
for almost a decade, including a lengthy peri- 
od with ICOM. America. She currently serves 
as Marketing Manager for Advanced Electron- 
ic ApplicalJons (AEA) of Lynn wood, Wash- 
irrgton. 

Trade Sanction 



The price of amateur gear that operates 
above 400 MlHz couid double as the result 
of 8 proposed 100% U.S. Import Tariff on 
such gear. 

The fedemi Register of 8 May carries no- 
tice of a hearing by the United States Trade 
Represeniative, to review telecommunica- 
tions trade with Japan on 24 54 ay. The hearing 
Is being held pursuant to Sectfon 1377 of the 
Omnibus Trade and Competitiveness Act of 
1988, and, among other matters, will bring up 

to 73 Amateur Radh • August, 1989 



the possible imposition of a 100% trade tariff 
on atl radio gear from Japan capable of trans- 
mitting and receiving signals on frequencies 
at and above 400 MHz. 

The proposed tax is a response to certain 
Japanese restrictions on telecommunications 
trade* primarily in dealing with the use rn 
Japan of US-made third party radio and cellu- 
lar telephone products. The Japanese Min- 
istry of Post and Telecommunications has 
kept a cellular system that uses American- 
buill gear from operating in several cities, 
even though spectrum Is available for such 
services. 

New Part 9 7 



Released 



Amateur radio has a new Fart $7 reguta- 
tory base to gufde It into the 21 st century. 

This revised base was approved by all current 
Commissioners by unanimous vote on 31 
May. See details on this revision in this 
month's "Looking West,' 



II 



Ham Help, 
Tech Tips 



For the moment, we have few "Ham 
Help" or "Tech Tip*' items, so these sub- 
missions stand a good chance of running very 
soon. Send them to us in hard-copy, or upload 
them to the 75 BBS (see connect info beJow, In 

Thanks"), to the SiQs 'VHamhelp" and 



I J 



I i 



/Techtips.'* 



No Special 
Callsigns 



The FCC dropped plana to permit special 
amateur callsigns assigned by an entity or 
entitles in the private sector After reading 
all comments and proposals on PRB-3» the 
Commission said it recognized that, while the 
amateur community wanted this service, 
there was no way to implement it without di- 
verting funds from the current licensing sys- 
tem. Amateurs witl have to continue to make 
do with callsigns assigned at random by the 
FCC computerized licensing system. 

Commissioner Bias ? 

MImi Dawson, fonner FCC Commission^ 
or, joined ttie taw firm of Wiley, Rein, and 
Reiding. This is the same group of lawyers 
ttiat is handling UPS's lobbying effort for 
spectrum fortheir digital voice national dis- 
patch system in the reallocated 220-222 
MHz amateur band. 

President Bush is now considering, among 
others, Sherrie Marshall to replace Ms. Daw- 



son. Interestingly, Ms. Marshall is currently an 
attorney of the above-mentioned law firm! 

if Ms. Marshall is nominated and conflm^ed 
by the Senate, it would fikely be a blow to the 
amateur community in the matters of retention 
of current spectrum allocations and in issu^ 
such as the fight to reverse the reallocation of 
the lower 40% of 1 -1/4 meters to Land Mobile, 
Further, it would make it difficult if not impossi- 
ble for a three-member Commission to effec* 
lively and femparliaify deaf with the 87*14 real- 
location, possibly forcing the FCC to go to a 
four member or full five member level to func- 
tion on this issue. 

Armenia Followup 

Vem Riportella WA2LQQ, former AMSAT 
president, visited and Interviewed Leonid 
Labutfn UA3CR In Moscow, and learned 
from him that the six packet stations sent from 
the US to assist communicatfons for the Arme- 
nian earthquake will now be used in Proj^it 
Search, a networiic to help reunite families sep- 
arated by the quake disaster. 

The complete inten/iew between UA3CR 
and WA2LQQ covers just about every aspect 
of amateur radio and amateur space activity in 
the Soviet Union. This Interview was sched- 
uled begm running in serial form in the West- 
tink Report newsletter in late June. 

AN ARC BBS 



The Association of North American Ra- 
dio Clubs Computer Bulletin Board System 
will have moved back to Kansas City by 1 

July, The new BBS phone number is (913) 
345-1978, and the new mailing address is PO 
Box 11201, Shawnee Mission, Kansas, 
66207-0201. Use the same number and ad- 
dress to reach the Association of Clandestine 
Enthusiasts (ACE) radio monitoring organi- 
zation. 

Feedback Winner 



Congratulations to Ralph Tafei WA8RLV, 
this month*s feedback card draw winnerl Win- 
ners receive a free 1-year subscription to 73 
Magazine, Future feedback winners will be 
listed in ^*Feedback;' 



Thanks! 



. . .to aft those follcs who contributed to 
this month *s QRX. They are Westlink R^xm, 
220 Notes, N6AHU, and W5KNE. Keep those 
ham radio related news reports and photos 
rolling in to 73 Magazine, WGE Center. Forest 
Rd., Hancock NH 03449, ATTN: QRX. You 
may also submit news items to the 73 BBS at 
603-525-4438, 300/1200 baud, 8 data bits, no 
parity, and one stop bit. Upload items to the 
/QRX SIQ, 





w 



pacesetter in Amateur Radio 






Two in the Hand ! 



TH-75A 

2m/70cm Dual Band HT 

The new TH-75A Dual Band HT 
from Kenwood is here now! Many 
of the award-winning features in 
our dual band mobile transceivers 
are designed into one hand-hetd 
package. 

• Dual Watch function allows you to 
monitor both bands at the same time. 

• 15 watts on 2 meters and 70cmr 
S watts when operated on 12 VDC 
(or PB-8 battery pack). 

• Large dual mult i function LCD 
display. 

• 10 memory channels for each band 
stores frequency, CTCSS, repeater off- 
set frequency step information, and 
reverse. A lithium battery backs up 
memories. Two memories for ''odd 
split" operation. 

• Selectable full duplex operation. 

• Extended receiver range: 
141"163,995and 438-449.995 MHz; 
transmit on Amateur band only (Modifi- 
able for MARS and CAR Permits required. 
Specifications guaranteed on Amateur 
bands only.) 

• Uses the same accessories as the 
TH-25AT (except soft cases), 

• Volume and baiance controls, 
plus separate squelch controls on 
top panel. 

• Super easy-to-use! For example, to 
recall memory channel, just push the 
channel numberl 

• CTCSS encode/decode built-in! 
•Automatic Band Change (ABC). 

Automatically switches between main 
and sub band when signal is present 

• Automatic offset selection on 
2 meters. 

• Tone alert system for quiet moni- 
toring. When CTCSS decode is on. 
the tone alert will function only when a 
signal with the proper tone is received. 

• Four ways lo scan, including duBl 
memory scan, with time operated or 
carrief operated scan stop modes, and 
priority alert 

•Automatic battery saver circuit 
extends battery life. 




•Supplied accessories: Dual band 
rubber-flex antenna, PB-6 battery pack, 
wall charger, belt hook, wrist strap, 
water resistant dust caps. 

Optional Accessories 

• PB-5 Z2 V. 200 rnAh NiCd pack for t ,5 W 
output • PB-6 7.2 V 600 mAh NiCd pack 

• PB-7 72 y 1100 mAh NtCd pack • PB*8 

12 V 600 rnAh NtCd for 5 Woutput • PB-9 72 V 
600 mAh NiCd with built-in charger • BC-10 
Compact charger • BC'11 Rapid charger 



SfiecMBtions and prices subject to change without mitice or obifgatton 

Compiete servtce manuais are Bvaiiabh for aW Kenwood transceivefs and most accessorise 



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and PIT* SC-22 and SC-23 Soft case 

• SM 0*30/31 Speaker mics. • WR-1 Water 
resistant bag. 



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...pacesetter in Amateur Radio 





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Other features include dual receive, 
automatic mode selection, automatic 
repeater offset selection for FM repeater 
use, VFO or quick step channel tuning, 
direct keyboard frequency entry, 59 
memory channels (10 channels for sep- 
arate receive and transmit frequency 
storage), multiple scanning and multiple 
scan stop modes. The Automatjc Lock 
Tuning (ALT) on 1200 MHz eliminates 
frequency drift. Power output is 45 watts 
on 144 MHz, 40 watts on 450 MHz, and 
10 watts on 1200 MH^. (The 1200 MHz 
section Is an optional module.) 



• High stability VFO. The dual digital VFOs 
featufe rock-stabteTCXO (temperature com- 
pensated crystal oscillator) circuitry, with 
frequency stability of ±3 ppm. 

• Operates on 13.8 VDC Perfect for 
mountain4op DXpedrtions! 

• The mode switches confirm US6, LSB, 
CW, or FM seiection with Morse Code, 

• Duai Watch allows reception of two 
bands at the same time. 

• Automatic mode and automatic 
repeater offset selection, 

• Direct keyboard frequency entry. 

• 59 multi-function; memory channels. 

Store frequency, mode, tone information, 
offset, and quick step function. Ten memory 
channels for *odd splitr 

• CTCSS encoder built-in. Optional TSU-5 
enables sub-tone decode. 

• Memory scroll function. This feature 
allows you to cfieck memory contents 
witfiout changing tfie VFO frequency. 




O^mptet&s&vtce m^nusts are avsitat^m ;^- j- r^nwooiS imn&c^, ^ers and most accessQf^s. 
Speaftcmtcms. teatures. and pnces are subjea !o c^snge ivflfiotK notice or ot>itgaUor\. 



• Multiple scanning functions. Memory 
channel lock-out is also provided. 

• ALT- Automatic Lock Tuning -on 1200 
lAHz eliminates drfft! 

• 500 Hz CW filter btillt-ln. 

• Packet mdio connector. 

• Interference reduction controls: 10 dB 
RF attenuator on 2m. noise blanker. IF shift, 
selectable AGC. all mode squelch. 

• Other useful controls: RF power output 
control, speech processor, dual muting, 
frequency lock switch. RII 

• Voice synthesizer option. 
'• Compyter control option. 

Optional Accessories: 

• PS-31 Power supply • SP*31 E internal speaker 

• lfT40 1200 MHz module •VS- 2 Voice synthesizer 
unfl ♦TSU'5 Programmable CTCSS decoder 

• IF-232CCompLitennterface*MC-60A/MC-80/ 
MC-85 Desic mtcs • HS-5/HS-6 Headphones 

• MC-43S Hand mic • PG-2S Extra DC catsle 

KENWOOD 

KENWOOD U.S.A. CORPORATION ; 

COMMUNICATIOKS S.TEST EQUIPMENT GROUP | 

RO. BOX 22745, 2201 E. Dommguez Street |! 

Long Beach, CA 90801-5745 | 

KENWOOD ELECTRONICS CANADA INC, 
RO, BOX 1075, 959 Gana Court 
Mississauga, Ontario, Canada L4T 4C2 



Nyinber 4 on your Feedback card 



CTCSS, Fast and Cheap 



Low-cost PL tone generator 

by Ray Isenson N6UE 



So you've got a problem! Last 
night the repeater group voted 
to put your favoriie machine on 
PL, and you don't have a single rig 
with cress capability. Worse, 
hair of your rigs are so old you 
couldn't buy ^ modi Heat ion kit 
even if you had the money. The 
XYL (XYM> hasn't cooled down 
since you bought that new packet 
TNC. so there's no way yt>y could 
come up with the money for a tone 
board for the fancy all-mode that 
Santa brought last Christmas! 

Uncle Elmer to the Rescue 

Actually, if you can squeeze about seven 

dollars out ofthc kid's piggy bank: if there^sa 
Radio Shack or its ilk around: if you have a 
soldering iron: and if you're not above a 
small challenge* your old Uncle Elmer may 

have just the solution for you. It should make 
a good one-evening project. 

What IS PL? 

Some > er^r^ ago Motorola introduced ' 'pri- 
vate listening (PL)'' to the commercial radio 
community. In one implementation, a tone. 
generally a subaudible frequency (67-210 
Hz)» is impressed on the transmitter's carrier 
along with the audio intelligence. A compan- 
ion, single-frequency demodulator at ihe re- 




Phoio A. 'Fhe completed PL board, 

ceiver enables the audio circuits only In the 
presence of this tone. The result is a form of 
.selective calling. 

Picture a master station with the ability to 
switch in any one of a number of different 
"calling'" tones. If there is also a remote 
receiver for each of these tones, remote sta- 
tions will hear only those transmissions ad- 
dressed to each of them. The master station 
can talk whh any secondary station without 
bt>thering ojXTators at the other receivers. 
Additional circuitry' maintains ihe privacy of 
the return link. 

Some members of the amateur community 
adapted the concept to VHP and UHF radio 
when repealers became popular, but not with- 



out dissenters. Unfortunately^ its 
early use by amateurs was intend- 
ed to deny repeater access to non- 
members. Many of us, including 
myself, believed strongly that this 
was contrary lo the open spirit of 
amateur radio, and we refused to 
have anything to do with it. More 
recently, we've had to reconsider 
our position, as more amateur and 
commercial repeaters have taken 
over the hilltops. Using PL helps 
combat intermodulalion and other 
interference problems. 

How PL Works 

In iJie normal scheme of things, the re- 
peater receives an FM signal and the detected 
carrier switcheii in the transmitter through 
COR, or Carrier Operated Relay. The typical 
PL operating repeater uses the detected sub- 
audible frequency tone, as opposed to the 
detected carrier frequency, to pull in the 
transmit relay. In some cases the operation 
requires a continuous subaudible tone to 
maintain contact. In others the tone serves 
only to pull in the relay: the carrier or some 
other signal holds it in. In the latter case the 
system generally will function even if the 
tone is continuous. To work through the pro- 
tected machine, we only need to provide a 
lone at the right frequency and amplitude to 



vcc 

13.8V 



X 

cr 

(SEE TEXT) 
ffl 



1 



C2 [MYLARl 

-^1 



C3 (MYLAR) 

-^1 ■ 




R9 



VR{T) 
(SEE TZt.^) 

R(T) 




TONE OUT 



RIO 



Figure I. Hie PL Tone Generator Circuit, 



73 AmatBur Radio • August. 1989 13 



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CTCSSTONeaOARD 
hHEQUENGY SETTING CHAFiT 








































































































































1 
1 








































































































































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80 


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120 i40 i60 580 

FREQUENCY tM HERTZ 


200 


220 





Figure 2. Graph showing rone frequency vs. mning resistance, to help you choose the righi 
resistance combination for a desired subaudihle tone. 



satisfy ilie repeater- Figure 1 is a schematic of 
a very simple circuit designed to do just thai. 

Uses Common Partes 

There arc no high cost orhard-io-find parts 
in the circuit. Your local electronic parts 
store is a good source. The total cost for the 
unit« assuming that you have none of the parts 
on hand, is less than $7. The only critica] 
parts are C2 and C3. two 0.1 pF Mylar™ 
capacitors- These must be Mylar, poly- 
styrene, or a similar material to minimize 
tcjnperaturc sensitivity and assure frequency 
stability. The common RF bypass type disc 
cap will not work. They are too temperature- 
sensitive! Although a well-equipped hobbyist 
could make a custom PC board for the pro- 
ject, the predrilled Multipurpose Board (RS 
276-150) for 99C ts not only adequate, it's 
probably preferable. 

The R(T) and VR(T) resistors connected in 
series, and the previously noted 0.1 \x¥ ca* 
pacitors. let you tune to the desired PL fre- 
quency. The commonly accepted range of 
subaudible frequencies extends from 67 Hz to 
210 Hz. The unit that you assemble will not 
be able to tune in this entire range, but it 
won't need to. The computer or electronics 
technician will have picked the frequency for 
your machine. Your board will have to be 
able to set that frequency to within a Heru. 
This circuit offers this capability. 

Setting th€ Ri^ht Tone 

Examining the circuit diagram, you will 
notice a resistor identified as R{T); a variable 
resistor, VR(T): and a47kD resistor between 
pins I and 2 of the dual operational amplifier. 
The three resistors and the 0. 1 |iF capacitors 
are the basic frequency-determining compo- 
nents of the circuit. 

To give you the freedom to pick among a 
wide range of frequencies, and set your ma- 
chine precisely* the circuit uses the two resis- 
tors in series. Your task is to select a fixed 
resistor of a value yielding a tone in the de- 
sired range. The variable resistor is used 
for fme-tuning. 

Figure 2 shows total resistance versus 



frequency in Hz. The curve was experimen- 
tally determined with 1 % components as the 
critical frequency determining elements. Use 
it It) make the initial selection of the fixed 
rcjiistor, R{T), as you design your CTCSS 
board. 

Why the initial setting? As previously not- 
ed, the curve was generated with 1 % toler- 
ance components for the O.I llF capacitors 
and the timing resistors: a most unlikely thing 
to realize. Expect values more like ±5% 
resistors and capacitors. So well select a 
resistor that is some- 
what smaller than 
the curve calls for, 
and use the variable 
resistor, VR(T), to 
make up the differ- 
ence and allow for 
some tuning flexibil- 
ity. The value of 
the variable resistor 
should be slightly 
greater than the dif- 
ference between the 
value of the fixed re- 
sistor and the value 
of the next larger 
one* 

Why not just use a 
potentiometer in the 
first place? The 
smaller the total val- 
ue of variable resis- 
tor, die more precise 
the sening you can 
make. The variance 
in resistance per de- 
gree of rotation of 
the potentiometer is 
less! Now, if you 
fmd that your initial 
choice won't let you 
tune down to the de- 
sired frequency, you 
can replace the fixed 
resistor with the next 
higher value. 

With curve- fitting 



analysis, we find that the Resistance/ Fre- 
quency curve can be closely approximated by 
the equation: 

Frequency = 3896 x ((Rx47000)/(R+ 47000) I'^'^^^ZZ 

where R is the sum of the fixed and variable 
tuning resistors. I note this equation to em- 
phasize that if you replace the feedback resis- 
tor across the first part of the dual operational 
amplifier with something other than the 5%, 
47,000Q device specified, you may not be 
able to use the curve in Figure 2 to select your 
tuning resistor. In other words, change that 
resistor and you're on your own! 

Choosing the Resistor Combo 

This project was originally undertaken to 
build PL tone generating boards for members 
of a 2 meter repeater group in the California 
Central Coast area. Their repeater was sub- 
jected to some intermodulaiion from two 
commercial paging service machines situated 
on the same hilltop. The offending RF fre- 
quencies, unfortunately, were exactly 600 
kHz apart! These two fresqucncies, beating 
with the repeater transmitter output, resulted 
in an annoying *'grunch" at the repeater's 
input frequency. The trustee demonstrated 
that the PL technique circumvented the prob- 
lem, and he opted to put his machine on PL. 

He selected a frequency of 103.5 Hz for the 
PL tone. Using thai frequency as an example, 
and referring to the curve in Figure 2, the 
vertical dashed line that intersects the abscis- 
sa at 103.5 Hz represents the selected design 



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73 Amateur Radio * August, 1989 IS 



line. A honzonial line drawn from ihe inter- 
s^rtion of ihe vertical line aiKl the curve to an 
intersection with the vertical scale, suggests 
the need for loiai timing resistance of approx- 
imately 5.5 kQ. 

The closest 5 % , 14 -watt resistor offered by 
Radio Shack is 47000. The next higher value 
of '4 -watt resistor is 10k, The cloijesi vari- 
able to the 53k unit we need to get the run- 
ability ( 1 0-4. 7) is Radio Shack's 5k PC board 
potentiometer. This combination worked well . 

If you have access to a more complete se- 
lection of electronic components * a I or 2k 
potentiometer and a SIOOO fixed resistor 
might be even better (\ir increasing the setting 
sensitivity, ff, because most of your compo- 
nent tolerances stack up on the high side, the 
highest achievable frequency is just slighdy 
low, shunt the fixed resistor with a large 
value (perhaps one of the 47k resistors still in 
die bubble pack). If that doesn't work, you'll 
have to go to a higher value resistor » but we 
have not encountered this problem. 

From an examination of the curve in Figure 
2, it Ls clear that a significant change in the 
tuning resistor is needed for a given change in 
frequency at the lower frequency end of the 
curve, and a very slight change at the higher 
frequency end. Because of this. I would be 
leery of using the circuit for tones above 120 
Hz. At that end, even slight temperature vari- 
ations could throw the circuit outside of the 
0.3 to 1 .0 Hz tolerance that most PL systems 
accommoJiiie. The answer is to use a PL 
tone in the lower end of the band, if possible. 
In regions subject to wide temperature varia- 
tions> it would be wise to stay with tones 
under 100 Hz if you are selecting the PL 
frequency. The unit in my car operates from 
the low 30s to slightly over 100 degrees 
Farenheit. It has never failed to access the 
repeater. Ambient temperature may never be 
a problem for you. 

In Praise of Predrtlled Boards 

If this is your first experience wMth a 
predriilcd board, you're in for a pleasant 
-surprise. Except for the fact that you have to 
be very careful to avoid solder bridges, 




Fhota B. The PL board installed in ihe Conarc 452 2m rig. 



predriilcd boards simplify small project as- 
sembly. Radio Shack offers several varia- 
tions of these boards. You could use either 
the RS 276-149 or 276-150 board to make 
two of these CTCSS tone boards. I prefer the 
150 board because it has strings of connected 
pads 10 simplify construction. You may 
prefer the flexibility of the other. For group 
projects, it'll be cheaper to cut up one of the 
larger boards into suitably sized pieces. 

Make the board as small as possible, to fit 
inside the transceiver. The largest compo- 
nents are the potentiometers and the Mylar 
capacitors. You can gel it as small as 0.8 x L5 
inches. Photo A shows the completed board. 
Youll find space to mount the unit inside 
most mobile 2 meter transceivers, but for an 
HT, you will probably have to resort to exter- 
nal mounting. This has been done without 
trouble as long as the 0*001 |jF RF bypass 
capacitor was used on the power lead» as 
shown on the circuit diagram, and all leads 
were kept short. 

Once all of the components are in hand, it's 
a good idea to make a sketch showing the 
physical layout, If you use a board with con- 



Parts List for the CTCSS Tone Board 


Component 


Type 


Cost 


Fixed Resistors V4-Watt. S% 


flS.RIO l00On(Pkg.of5) 


S .39 




R2, R3 


33kO@ .39 




R1.R4,RS,R6,R7,Re 


47kD@ .78 




R(T) 


Seeanicle@ .39 


Mylar Capacitors, SO WVDC 








C2,C3 


0.1pF(Pkg-of2)@ JB 


Capacitors, RF bypass 








CI 


0.001 pF@ .49 


Potentiometers* Mi-Watt 








VRt 


250® .59 




VR(T) 


Seearticle^ .59 


Integrated Circuits 








U1 


LM1458ii^ .99 


Project Board 




Seearticle@> .99 


TOTAL COST 




$6,39 



Table L 



nected pads, such as the RS 276-150, make 
sure that all items entering or leaving each 
'*node" are connected— even if you have to 
jumper strips together to do it. If you use the 
separate pads, as on the RS 276-149, remem- 
ber that ycju'll have to "wire" the pads to- 
gether after soldering the component)^ to the 
prcd rilled board. Show these wires on your 
sketch* (Note: I use very fme wire to connect 
the pads and create ** solder bridges'* be- 
tween those pads that I want to connect.) 

Check to make sure that you make all of the 
connections called for in the schematic, if the 
circuit doesn't oscillate at the desired fre- 
quency, you can bet that the diagram didn^t 
suppon the circuit. It is a good idea to try a 
few different layouts to find the one that fits 
your transceiver the best: it's better to do it at 
this time dian after the board is all made up! 
Cardboard cutouts are useful for sizing. 

As of this writing, the circuit has been used 
in more than twenty transceivers of many 
different types. These include the Conarc 
452. the Azden PCS 4000. the Kenwood 
TR 7850, the Heath HW-2036. other Ken- 
woods, both newer and older than the 2850, 
several different Midlands, an ICOM 22A, a 
more recent ICOM, and a few different 
models made by Yaesu. Other than the diffi- 
culty of squeezing the board into a clear place 
in the cabinet, the only problem we encoun- 
tered was finding a suitable point to insert the 
signal, 

Having the Right Connections 

DO NOT— REPEAT— DO NOT try to in- 
sert the tone into the microphone circuit, Sig- 
nal shaping in that area is almost guaranteed 
to attenuate and distort the tone to oblivion. 
User manuals for many fairly new 2 meter 
rigs suggest a connection point for the PL 
tone generator. Read your manual before tak- 
ing someone else's advice! 

If the manufacmrer didn^i offer a solution, 
use the schematic to locate the deviation ad- 
just potentiometer. Tone input at the lip end 
(preferably) » or center tap of that potentiome- 

Continued on page 40 



16 73 Amateur Radio * Aug u St . 1 9 89 



M 



Number S on your Feedbacfc card 



AM PROFILES 




Photo A. Diane Magen KG5CS. ag& 
fift&en. Hot Springs, Arkansas^ Her 
career plans include aviation, engi- 
neering, and mBthematics. 

Friends the World Over 

Diane R. Magen KG5CS m a fifteen-year-old 
high school sophomore in Hot Springs, Arkan- 
sas. In addition to the lime she puts in to 
maintain her "A" average m school Diane 
manages to find time to study In ground schoof 
for her private pilot's license. 



There are no "average" hams! 

Diane participates in YL contests and en* 
joys the security of a 2 meter rig in the family 
car Other interests include baton twirling, 
needlepoint, and traveling. 

Writes Diane, '*No matter where you travel, 
you always have friends. Amateur radio Is a 
wonderful fraternity!*' She had a wonderful 
opportunity last summer to meet face to face 
some distant acquaintances made over the 
atr She and her mother (also a ham) travelled 
aboard the Ocean Peart, which sailed to Sin* 
gapore, florobudurand Bali, Indonesia, Mani- 
la, and Canton. During this trip, they met with 
Roger DU1KT. Phil VS6CT. and Ian G4LJF. 
8y the time you read this. Diane KG5CS will 
have estplored Monaco. Florence. Rome, 
Venice, the Lipari Isiands. Corfu Island, Du- 
brovnik^ Yugoslavia, and Paris. She will also 
have visited Vince Sullivan N2UN at the Unit- 
ed Nations. 

This coming school year, Diane KG5CS 
hopes to work as a page in the House of Rep- 
resentatives. 

Meet Another Southern Belief 

Be sure also to get in touch with Dorothy 
Livsay KC41QP when you're travelling 
through eastern North Carolina. This thirteen- 
yearold spends a lot of time working GW on 




Photo B. Dorothy Cfark KC41QP, 
thirteen years old, is an active 220 
MHz FMer. 

two 2a0 repeaters, NF4C and WA4DAN. She 
is a very active and enthusiastic ham. 

Dorothy KC4IQP and her father studied am- 
ateur radio together and became licensed at 
the same time This month, they plan to up- 
grade lo General. The^r Elmer, who sent us 
Dorothy's photo, prefers to remain anony- 
mous, but has been a ham for fifty-five years. 

In addition to amateur radio, Dorothy 
KC4tQP enjoys music and softball. Her cur* 
rent ambition is to attend the Coast Guard 
Academy. 



To obtstn gmdefines for sutmittrng Ham PfofHes. 
write or caii Joyce at 603-525^201 Ex. 55 J, or down- 
load them from the 73 BB$/73m&g StG. {PH: 603- 
525-4438, 8 data bitSf no parity, or}e stop bit) . 



Feedba ok 



In our continuing effort to present the best in ama- 
teur radio features and columns, we recognize the 
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Articles and columns are assigned feedback 
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To save on postage, why not fill out the Product 
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Feedback! Title 

\ Welcome Newcomers 

2 Never Say Die 

3 QRX 

4 Home-Brew: CTCSS, Fast and 
Cheap 

5 Ham Prafiles 

6 Feedttack Index 

7 Review: Kantronics KAM 
S Hdme-Brew: COCOA'-A 

COllinearCOajtial Array 
9 Review: Amcntron AL-80A 
to BtKik Review: Uno, Dos^ Cuairo 
1 1 Rev k w : Ramsey COM -3 
i2 Hoine-Brcw: Control Your Rig 

from a PC 
13 Review: Ramsey SR-I Receiver 

15 Home-Brew: Full-Wave VHF 
Vertical Antenna 

16 Find Your Signal the First Time 

17 J£Z— Jugendeicktrankzenirum 
IS Home-Brew: Need FM? 

19 Home-Brew: lOGHzRFPreamp 



Feedback* Title 

20 Home-Brew: IF 

Cheap 

2 1 Aerial View 

22 Circuits 

23 RTTY l-oop 

24 Homing In 

25 Hamsats 

26 Ask Kaboom 

27 Looking West 

28 New Products 
2P QR? 

30 Special Events 

31 Above and Beyond 

32 Ad Index 

33 Letters 

34 TectiTips 

35 73 International 

36 Ham Help 

38 Dealer Directory 

39 Index 8/89 

40 Barter 'n' Buy 
4i Propagation 



7$ Amateur Radio • August. 1989 17 



Number 7 on your Fe«dbftck card 



73 Review 



by Brian Lloyd WB6RQN 



Kantronics KAM 

Versatile multi-mode data controller. 



Kantronics, Inc. 

1202 E,23r(J Street 

Lawrence KS 66046 

(9 13J 842-7745 
Price Class: $320 



The Kantronics KAM is an all-mode com- 
puterized interface that wilt send and re- 
ceive CW, packet, RTTY, ASCII, and AMTOR. 
The KAM can be used with a personal comput- 
er to receive weather facsimile (W£FAX) 
broadcasts. 

The Hardware 

The KAM Is a modem-sized box, 22.5 k 14,7 
X 4.7 cm. The front pane! has two push-button 
controls, one for power and one to select the 
FM Of AM (ilmiier-less) operation of the HF 
modem. Ttie rest of iWe fronl-panet conlrots 
are all LED status indicators, plus an easy-to- 
read green bar graph tuning indicator. The 
back panel has two radio connectors, a con-^ 
nector for the computer or terminal, and a 
connector for power. 

The KAM operates at 1 2VDC at 260mA. The 
power connector is standard coaxial, like that 
found with most small radios and accessories 
today. Kantronics provides a small 12VCX; at 
300mA power cube with the KAM. The low- 
power 12 volt operation makes the KAM a 
natural for portable or mobile operation. You 
have the options of providing operating power 
on one of the pins of the computer interface 
connector, or on the VHF radio connector, to 
reduce the number of cables. 

The unit connects to your computer or ter- 
minal with a standard RS-232 DB-25 connec- 
tor. This connector is factory configured for a 
standard RS-232 DCE (modem) connection. 
This means that you can probably unplug the 
modem from your computer and plug the KAM 
In its place with no other wiring changes. The 
KAM computer interface supports all the stan- 
dard modem signals, so your terminal pro- 
gram may be used without modification. Alter- 
natively, you may choose to use Kantronics* 
terminal program called "Kanterm" (I did— 
riKjre on this later). 

If youf computer does not support RS-232 
signals (the Commodore 64 and VIC-20 imme* 
diately come to mind) you will want to open the 
KAM and change jumper K7. This changes 
the controller output to the computer to TTL. 

A word of warning: Pin 25 of the computer 
connector is "hot'* with 12VDC. Make sure 
that pin 25 of the computer interface is not 
Inadvertently grounded through the com- 
puter. Damage to the KAM and/or Ihe conv 
puter could result. Play it safe and use an 
RS-232 cable that docs not provide a connec- 
tion to pin 25, 

There are two radio connectors: one for HF 
and one for VHF packet. The HF port is an 
a>pin female DIN jack. CW. RTTY, AMTOR, 
and low-speed (300 baud) packet are support- 
ed from this connector. The VHF port is a DB-9 
female connecior identical to the radio ports 

IS 73 Amateur Radio • August, 1989 




Photo A, The Kantronics KAM—a multi-mode 
data controller. 

on the KPC-2, the KPC-4. and the KPC-2400. 
If you have one of these other Kantronics 
products you can use the radio cable inter- 
changeably with the KAM, The VHF connector 
on Ihe KAM supports 12O0 baud VHF packet 
only. 

The Manual 

With a device this complex (the KAM can do 
a great deal) the manual is VERY important. 
Almost nothing about the KAM is intuitive (al- 
though it will t>e very familiar to anyone who 
has used TNCs before). The manual is com- 
plete, albeit somewhat terse. Everything you 
need to know is in there, but you might miss it 
if you do not read carefully. I strongly recom- 
mend that you read the manual, especially the 
part about interfacing the radios and the com- 
puter, from beginning to end tjefore you at- 
tempt to connect and use the KAM. 

There are MANY commands for controllmg 
the KAM (I counted 165). The manual does a 
reasonably good job of covering the most im- 
portant commands and walking you through 
gettfng the KAM operating. I read the section 
describing ail the commands before I tried 
operating because there are some differences 
between Ihe KAM command set and the com- 
mon TNC command set. 

The only section of the manual I found at ail 
difficult to understand was the section on mul- 
tiple connections (being connected to more 
than one other station concurrently). I cannot 
really blame Kantronics for the confusion. 
Kantronics Chose to be compatible with the 
multiple connect format used in the TAPR 
TNC. I find this format is awkward to use. The 
KAM manual does as good a Job of explaining 
the convolutions of multiple connections as I 
have seen anywhere. (This is one of the rea- 
sons that i have personally switched to using 
the KA9Q TCP/IP packet program for my 
packet operations. With KA9Q TCP the com- 
puter does all the work keeping the sessions 
separate, and I don't have to worry about it.) 

Connecting Ihe Computer 

The first step in getting the KAM to operate 
was to establish communications between it 
and the computer or terminal I started out 
using both my standard terminal program and 
the Kanlronics-provided Kanterm program. I 



finally settled on Kanterm since I liked the split 
screen display with separate windows for data 
received on the HF port, data received on the 
VHF port, and keyboard data. Kanterm does a 
good job of formatting the screen and keeping 
things visually separate without hiding the ac* 
tual exchange of commands. 

My only complaint about Kanterm it is that it 
erases the content of the windows if you 
change the window format {if you change from 
horizontal to vertical windows, from one to two 
windows, etc.). The information that was con- 
tained in the windows however, is not lost. It 
can be retrieved with the scrollback function, 

I did have one technical problem with 
Kanterm (the PC version). Kanterm did not 
work with either of my computers the first time, 
although my terminal programs, Bitcom and 
Procomm, worked just fine. The problem 
tumed out to be the cable between the KAM 
and the computer. It seems that some of Ihe 
RS-232 control signals are not asserted by the 
KAM» and Kanterm can't or won't initialize the 
RS-232 port. The fix was to use the 'Hhree- 
wire" RS-232 cable described in the KAM 
manual, and lo add the jumpers on the com- 
puter side of the cable (connect pkn 4 to pin 5 
and connect together pins 6. S. and 20). This 
solved the problem and allowed Kanterm to 
run normally. 

I spent plenty of lime properly interlacing 
the radios to the KAM. A quick and dirty inter- 
facing job fs liable to lead to poor performance 
because neither the radio nor the KAM are 
likely to see the proper signal levels. 

VHF Port Connections 

This is straightforward^ since there are only 
four signals you need to worry about: audio 
out (to the mike Input on the radio), audio in 
(from the speaker], push-to-tatk, and groufKi^ 
There is an optional external carrier detect 
signal but that is very rarely used. Since I 
already have a KPC-2 connected to my 2m rig 
(an ICOM IC-245) I used its cable to connect 
the KAM. 

It's very Important to set the signal level 
from the KAM lo provide 3 kHz deviation of the 
VHF FM transmitter. There is a problem doing 
this because the KAM provides only three 
jumper-selected choices for output level: low, 
high, and much too high. I had to change the 
value of one of the resistors on the circuit 
board (R-12) to gat the proper level for my 
transceiver. Fortunately, the manual clearly 
describes the procedure. This was not a prob- 
lem for me because I am comfortable using a 
soldering iron to make changes to a circuit 
board. Still, it would have t>een much nicer if 
Kantronics had provided a pot for output level 

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73 Amateur Radio • August. 1989 t9 



The manual indicates that the VHF modam 
is sensitive to Input level. Kantronlcs suggests 
a maximum input of 50 mV to the KAM. The 
easy way to set this is to hook the KAM's VHF 
audio Input to the speaker of the transceiver 
and then adjust the volume control for 50 mV 
while receiving packets. 

A nice feature of the KAM is that rt allows the 
user to select from three different receive 
equaltzation settings (jumper K-1). With my 
configuration, the INC and/or KAM connect- 
ed to the discriminator through a buffer, I 
found that the position that disabled equaliza- 
tion provided the best results. Connecting the 
KAM to the speaker Jack would probably have 
required partial or full equalization. The KAM 
i® shipped With iumper K-1 set to the full EQ 
position. 

HF Port Connections 

For this, you have to build your own cabte. 
The HF connector on tfie KAM supports the 
foikiwing signals: aud^o in (from the speaker 
or phone patch output of the rig), audio out (to 
the mike or aox audio input of the rig), key out 
(to the CW key jack on the rig), FSK out (to the 
FSK input on the rig), PTT out (the PTT line on 
the rig), external carrier detect (from the 
squelch on the rig), and ground. I tested the 
KAM wrth a Kenwood TS'940S transceiver 
and most of the connections went to the ac- 
cessory jack on the back of the transceiver. 
The two exceptions were the key and the FSK 
signals. 1 had to run those signals to separate 
plugs. 

Setting the level for AFSK operation was 
much easier. Most HF rigs allow you to set 
transmit levels from the front panel usually 
withthemikegain control. Use jumper K-5(HF 
AFSK output) to select the lowest output from 
the KAM that will provide full output from the 
rig. Most rigs include instructions for connect- 
ing RTTY equipment; follow them* 

VHP Packet Operation 

After I got my computer, Kantemi, KAM» 
and my radio all talkmg to one another I decid- 
ed to try the KAM out on VHF packet. If you 
have used a TNG before, nothing could be 
simpler, The commands are all familiar and 
work in a similar manner. The KAM performs 
as well as any other TNC I have used on VHF 
packet. 

Kantronics has added a few commands that 
have the potential to make packet operation 
more effective. In addition to the DWAIT com- 
mand (used to prevent collisions between 
packets from end-user stations and 
digipeaters), Kantronics added the PERSIST 
and SLOTTIME commands. These two com- 
mands implement something call p-persisteni 
CSMA which promotes belter channel shanr>g 
amongst the users. Users in your area will 
notice an improvement in throughput and a 
reduction in retransmissions as more stations 
begin using p-persistent CSMA. 

After I used the KAM to check into 
the bulletin board and have a OSO or 
two, I tried it out with TCP/IP, my usual 
packet operating mode. The KISS 
mode worked just fine. I transferred a 
couple of files and several mail mes- 

20 73 Amateur Radio • August, 1989 



sages, and had a QSO, all at the same time. 

HF Operations 

The KAM is as good on VHF as any TNC. 
but the reason to buy It is to get the HF packet, 
RTTY. AMTOR. and CW capability. Any dis- 
cussion of these modes requires a discus- 
sion of the design features that make them 
possible. 

One of the keys to the fte^^iblfity of the KAM 
is the programmable HF modem. The modem 
can be programmed for fust about any baud 
rate (up to 500) and any two tones. When you 
select RTTY, HF packet, ASCII, AMTOR. or 
CW. the KAM automatically chooses the stan- 
dard modem settmgs used with that mode. If 
you wish, you may change the baud rate, the 
mark, or the space tones. This can be a real 
boon to experimenters. You can also optimize 
the tones to your particular rig. 

A switch on the front panel of the KAM se- 
lects either FM (limiter) or AM (Iimiter4ess) 
operation of the demodulator, I noticed a small 
but discernible performance difference be- 
tween the two modes^ The AM mode seems to 
have the edge on weaker sfgnals, while the 
FM mode seems to have the edge on stronger 
signals when QRM Is present. It is nice to be 
able to choose between the two. 

Tuning Indicator 

This is part of the HF modem and is used as 
an aid to tuning RTTY, ASCII, AMTOR. Pack- 
et, WEFAX, and CW. The green bar graph 
display is labeled with mark and space at op- 
posite ends. If you have selected the proper 
shift and tuned the signal properly, the bar 
extends fully from the center to both ends^ 

The tuning indication on CW is slightly dif- 
ferent. When no signal is present the bar 
graph segment nearest the left (mark) wiM be 
lit. When the other station is key down, the 
segment nearest the right (space) should be 
lit. Tune slowly untti this occurs. 

CW Ope ration 

The first HF mode I tried was CW operalion, 
H^re, the KAM allows you to independently 
select filter bandwidth (the standard is 200 Hz, 
but it may vary from 50 to 1000 Hz), and the 
filter center frequency. The KAM keys the 
transmitter using a reed relay so it can work 
with reiatively high voltage grid*block keying 
circuits. Using a relay also ensures that polari- 
ty is not a problem. 

The manual cialms that the KAM can auto- 
matically track CW sent at speeds up to 20 
WPM different from the value set with the CW 
or CWSPEED commands. This means that 
you can set it for 20 WPM and the KAM will 
lock and track just about anything between 
and 40 WPM. From what I could teil it did. 
Although the KAM will track any speed, the 
KAM sends CW at the speed set by the CW or 
CWSPEED commands. Thrs means that you 
have to guess how fast the other guy is send- 
ing and set the KAM appropriately. 

The KAM did a good job of copying a good 
fist or machine-sent code, II pretty much falls 
apart trying to copy a poor fist. The KAM is 
also picky about mter-character spacing. If the 
sender sends the characters at a faster rate 



but then inserts more time between charac- 
ters the KAM wilt display the characters sepa- 
rated by spaces (as if each character is a 
separate word). It is readable but annoying. If 
you are copying someone with a keyboard or 
using a keyer, the copy is flawless. I found it 
great fun to copy the high-speed maritime CW 
transmissions. 

Once you have selected the CW mode the 
KAM tnes to copy everything. Pressing '*con- 
tTol<;*' followed by *'T" (^CT) enables the 
keyboard ^ and everything you type will be 
sent. Pressing "control-C* followed by "R" 
(^CR) retoms the KAM to the receive mode. 

Several keytxiard keys are mapped to pro* 
duce special Morse $ymtx>ls such as AR, BT, 
AS, KA, SK, KN, AA. and SN. it takes a tittle 
getting used to. 1 solved the problem by mak* 
ing small adhesive labels and attaching them 
to the computer's keyboard. 

RTTY and ASCII 

RTTY and ASCII are both character asyn- 
chronous data transmission. Their sole differ- 
ence IS that RTTY uses the 5^Dit Baudot code 
and ASCII uses the 7-blt ASCII code, I didn't 
test sending and receivmg ASCII because I 
never found anyone else using ASCII. Since 
there is no other difference between RTTY 
and ASCII operation, I expect that my com- 
ments about RTTY will apply to ASCII as welL 

Receiving RTTY is simple. Just select the 
shift and the baud rate, then tune the receiver 
for the proper indication on the bar graph tun- 
ing Indicator. The tuning indicator also makes 
it obvious if you select the wrong shift. On the 
ham bands I found 45 baud (60 WPM) with 1 70 
Hz shift to be the rule. Tuning was simple and I 
could copy almost anything. 

How you choose to send RTTY depends on 
your rig. Most SS8 rigs do not have a special 
RTTY mode so you must use AFSK. The tones 
from the KAM are fed Into the transmitter and 
the transmitter is operated on lower sideband. 
If your rig supports direct FSK (the TS-940S 
does) you can use that mode, but you lose the 
ability to select transmit shift from the comput- 
er. I tried both methods and they worked 
equally well 

One activity I particularly enjoyed was trying 
to copy commercial and private RTTY trans- 
missions. In this game you tune in a transmis- 
sion and try to decode it. It's easy to change 
shpft, baud rate, and irwersion "on the fly.'* 
This activity is more difficutt r>ow because tew 
of the commercial transmissions use charac- 
ter asynchronous clear-text transmission; 
most now use some transmission mode that is 
Indecipherable by the KAM, 

AMTOR 

After becoming comfortable with RTTY op- 
eration I decided to try my hand at AMTOR, a 
mode I have never used before. Before I couJd 
operate AMTOR I needed to understand some 
concepts. 

AMTOR is like a cross tsetween RTTY and 
packet radio operation. Data is transmitted in 
three character "packets/' using an error de- 
tection code. In this way, AMTOR is like pack- 
et radio. On the other hand, AMTOR is like 
RTTY because it uses the similar speeds and 




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shifts, and only one pair of stations at a time 
can yse a given frequency. 

Eacii AMTOR station on a frequency must 
have its own unique identification (SELCAL). 
The SELCAL is a 4-character identifier used to 
call and establish communications with anoth- 
er station. To save you time the KAWI automati- 
cally creates a SELCAL entry from your call- 
sign. In my case my call, WB6RQN, was 
permuted into WRQN for the SELCAL. The 
KAM provides the option to manually enter the 
SELCAL of your own choice. 

To get started with AMTOR I used the LAM- 
TOR (Listen AMTOR) command to "eaves- 
drop" on other AMTOR and commercial 
SITOR transmissions. This gave me practice 
in recognizing and tuning AMTOR signals. 
The KAM copied these signals well, with only 
an occasional lost or duplicated "pacltet" (du- 
plicated when the receiving station requested 
retransmission of a packet). Copy of transmis- 
sions using the Forward Error Correction 
(FEC) mode B was almost always 1 00%. 

Active contacts require a special protocol 
because AMTOR is designed as a reliable 
station*to-slation mode of operation. Most 
AMTOR QSOs use the Automatic Request for 
Retransmission (ARQ), Mode A. This requires 
that the two stations "handshake" (the receiv- 
ing station must "ACK" each transmitted 
packet). This makes calling CQ an interesting 
prospect. 

To call CQ with the KAM, you enter AMTOR 
mode with the AMTOR command and do not 
specify a SELCAL. This places the KAM in 
standby mode (ready to receive). Key the 
transmitter with the controt-C T (^CT) com- 
mand (same as with CW and RTTY) and type a 
standard 3x3 call making sure to include your 
SELCAL. End the CQ with the conlrol-C R 
command (^CR). If someone else wants to 
respond they will zero-beat your CQ and then 
call you using your SELCAL. The KAM recog- 
nizes your SELCAL and begins the handshak- 
ing process with the other station. 

The link is turned around with the character 
combination '" + ?'*. This telis both the KAM 
and the other station that you want to turn the 
link around so the other station can send 
(this is equivatent to the word ''over" tn voice 
communications). When you are done with 
a QSO and wish to break the link you enter 
the sequence control-C X (^CX). You have 
the option of "breaking" the other station 
when he/she is sending by entering the 
/^CT command. This forces link turnaround 
immediately, 

1 had absolutely no problem getting the 
KAM's AMTOR to work with the TS-940S. If 
you have problems getting AMTOR to work I 
would suspect the rig before I would suspect 
the KAM. AMTOR places significant stress on 
the rig because it is constantly switching ffom 
receive to transmit and back again several 
times a second. Some rigs just can't switch 
fast enough. A good thing to look for in a rig for 
AMTOR is full QSK capability in CW. That 
indicates that the rig is designed to switch 
rapidly from receive to transmit and back 
again. The TXDAMTOR (transmit delay AM- 
TOR) command allows some adjustment for 
rigs that are slow to switch. 

22 73 Amateur Radio * August, 1989 



One other significant point in AMTOR 's fa- 
vor is that it does not require massive amounts 
of power to be successful. For this reason I 
imagine that most stations run barefoot. An 
amplifier just adds to the transmit delay and 
may even make it impossible to establish an 
AMTOR connection. Even with significant 
amounts of QRM or QRN^ the KAM seems to 
be able to slip the data through. 

HF Packet 

The big feature of the KAM for me is its HF 
packet radio capability. After trying out RTTY 
and AMTOR p I felt very comfortable with the 
computer/rig/KAM combination. 

The default values for packet operation 
work pretty well with one exception; Kantron- 
ics selected the default value for MAXFRAME 
to be 128 octets (bytes or characters). This is 
much too long for HF packet. I shortened it to 
32 octets and operated that way. 

! had absolutely no problem running HF 
packet. The KAM automatically selected 200 
Hz shift (1 600/1 800 Hz tones) and 300 baud, I 
used lower sideband and AFSK operation 
without any problems. Setting the receiver's 
bandpass to 500 Hz seemed just about opti- 
mum. In sum: It works well and was easy to 
se! up. 

WEFAX 

The last mode offered by the KAM is the 
ability to receive weather facsimile (WEFAX) 
broadcasts. For this mode the KAM operates 
strictly as a WEFAX modem. The actual pro- 
cessing of WEFAX pictures takes place within 
the computer. 

There is a surprise in store for you when you 
try to use the KAM to receive WEFAX; The 
signal must be connected to the VHF port! 
You may wonder about this after you took all 
the trouble to hook your HF receiver to the HF 
port, but that's the way it is. Perhaps a switch- 
box to allow switching the receiver to either 
the HF or the VHF port is in order. 

Kantfonics supplies two WEFAX programs 
for use with the KAM and a PC: MaxFAX and 
SuperFAX. I started out using the MaxFAX 
program, but wasn't pleased with its perfor- 
mance. On my computer with aCGA graphics 
adaptor the FAX pictures were jumbled on the 
CRT display but printed properly on the print- 
er. My other complaint was that MaxFAX lacks 
any onscreen key labeling or help. 

The SuperFAX program is MUCH better. I 
found it to be much more "friendly/' Super* 
FAX also properly displayed the pictures on 
the CRT display. SuperFAX ts larger and slow- 
er than MaxFAX, but that is a very small price 
to pay for the much improved performance. 

There is another feature of SuperFAX that I 
like very much; it comes with the source code 
to the program (it is whtten in BASIC). This 
should make it possible to make changes or to 
move the program to another computer with- 
out too much difficulty. I would like to see more 
vendors do this. 

Special Packet Features 

The KAM comes equipped with two special 
packet features not found in most other TNCs 
or multi-modes: a gateway function and a per- 



sonal packet mailbox. The gateway function 
permits the KAM to act as a crossband 
dtgipeater when tK>lh the HF and VHF ports 
are enabled. This means that packets may be 
picked up from the HF channel and digipeated 
on the VHF channel, and vice versa. 

To make the gateway work you must enter a 
different ID for the gateway. My ID (call) is 
WB6RQN-0 for local HF and VHF operations, 
and WB6RQN-1 for the gateway. Packets that 
arrive on VHF to be digipeated by WB6RQN-0 
are retransmitted on the VHF channel Pack- 
ets that arrive on the VHF channel to be 
digipeated by WB6RQN-1 are retransmitted 
on the HF channel. Likewise, packets that ar- 
rive on the HF channel to be digipeated by 
WB6RQN-1 are retransmitted on the VHF 
channel. 

I think that the gateway feature is a big plus. 
I expect it to be a very useful feature if and 
when we are granted permission by the FCC 
for unattended operation of HF packet sta* 
tions. Presently, you must be in the shack 
whenever the gateway is enabled. 

The second function is the personal packet 
mailbox (PPM). This permits people or BBS 
stations to connect to the KAM and leave or 
retrieve messages. In essence the KAM be- 
comes a small BBS with messages stored in 
the KAM's memory rather than on a disk- 

I do not expect the PPM to replace any 
BBSs but I do think that it can become a big 
part of the local BBS operation. One of my big 
complaints with BBSs is that you have to peri- 
odically check into them to see if you have 
received any messages. If there are many 
BBS users in your area this can become a 
painful process with several people trying to 
access the BBS and/or keeping it tied up for 
long periods of time. PPM can help alleviate 
this problem by allowing the BBS to automati- 
cally forward your mail to the KAM-running 
PPM. All you need to do then is to check the 
KAM for your mail. Sending mail works the 
same way: You prepare the mail in the KAM 
and let PPM automatically forward your mail 
to the BBS, 

The concept is very good. PPM performs as 
advertised. The only problem is that the 
KAM's memory is limited so you can not have 
many large messages stored. PPM, however, 
has the potential to significantly reduce BBS 
overload if people make use of it. 

Final Impressions 

The KAM has performed flawlessly for me 
for the SIX months or so that I have used it. 
After this much use I can safely say that the 
KAM is a very impressive product. It does 
everything that it is advertised to do, and does 
it well. For relatively little money Kantronics 
has provided a great deal of functionality m 
a very small package. From this point of 
view the KAM may be the ultimate station ac- 
cessory. 

If you are looking for a small, low-power, 
lightweight, all-purpose terminal unit to use 
with your personal computer, the KAM may be 
the answer. Ditto, if you are tired ol just rag- 
chewing on HF and want to do something 
really different. I recommend the KAM without 
any reservation. 



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COCOA— A COUinear 

COaxial Array 

Make COCOA your cup of tea. 



by James E. Taylor W20ZH 



Since 1970, 1 have used a straightforward, 
phased array for 75ni. This array is 
composed of two parallel dipjolcs a quar- 
ter-wavelength apart, with a ganged switch 
to control directivity by changing the lengths 
of the coaxial fecdlines to the separate 



A Fe^v Improvement Ideas 

Although IVe had great results from this 
system » old-fashioned ham curiosity led to 
several improvemeni atiempLs. 1 first looked 
at two-phased verticals. ^ These vertical radi- 
aiors were a quarter-wavelength high and 
apart, and uliimately, each included 73 quar- 
ter-wave radials. Ahhough eiecirically excel* 
lent, they never showed a consistent advan- 
tage over the horizontal system over several 
years of use, in spite of published material to 
the contrary. It\s likely the far-field ground 
losses at my location cancelled the vaunted 
low-angle advantages. 

I then looked at using three half- wave- 
lengths of coaxial cable, with inner and outer 
conductors interchanged, to provide a 
collinearin-phase amy* Balsley and Ecklund 
used such a scheme for a radar system at 49.8 
MHz/ However, space and height limita- 
tions made this system impractical on 75 
meters. What to do? 



Build On the Original 

Challenged by the above experi- 
ences, and by an ignorance of limit- 
ing factors such as ground losses, 1 
went back to my 2-element array to 
try to build on that. 

Recall that this system comprises 
two parallel half-wave elements 
positioned one quarter-wavelength 
apart. The center feed point of each 
element is supported a quancr- 
wavelength above the ground. One 
way to improve this system would 
be to add a half- wavelength ele- 
ment, collinearly, to each end of 
the two radiators, yielding a total of 
six half-wave elements! Such 
prospects led to a summer of excit- 
ing experimentation. This article 
describes the results of my summer 
fimS 

This article is in two parts. First, 
I describe the 3-elemem in-phase 
radiator (COCOA-3) and its exten- 
sion to a 6-elemcnt phased array 
(COCOA-6>, I then cover the 



shortened « more limited configuration I used 
for experimentation. 

The CoUinear-Coaxial Concept 

Antenna handbooks commonly show a 
collinear antenna comprising three half- 
waves in phase. They usually show a cen- 
terfed flat-top, three half- waves long. In the 
standard configuration (Figure 1), phase re- 
versing stubs, added at the ends of a centerfed 
dipole. put the instantaneous RF current in 
the end elements in phase with that in the 
center element. You can make these phase 
reversing stubs from open wire line or coax- 
ial cable. Normally* a shorted quarter-wave 
stub is used, but an open-ended half-wave 
stub would work just as welL The problem 
here, though, is that the dangling stubs are 
unwieldy at the lower frequencies. 

COCOA-3 

We can replace the dangling stubs with 
something sturdier and more com pact. See 
the basic shorted quaner-wa velengih of coax- 
ial cable, shown in Figure 2. When you apply 
an RF voltage of phase angle P' to the center 
conductor A at the open end, the stub causes a 
voltage phase lag of P ' - i 80 "" at the adjacent 
coax shield. Why this happens is easy to see. 



X/2 



I, 



X/2 



1 1 



1 1 



x/z 



1 



X/4 



1 



TRANS. 
LINE 



Figure I . Three half-wave sections phased using ' 'dangling stubs 



-A/2- 



*!•— '4/4 M a 1/4 ■■**■ 



i/1 



■t^I 



> 



i*M CClftV 



AA, 



3: 



J=T 



urn COAX 



Figure 2. Horizontal quarter-wave stub. It replaces the dangling 
stub and is less unwieldy and sturdier. 




Figure 3. COCOA-3, a 3 -element in-phase radiator. 



The RF is delayed by one quaner-cycle as 
it passes from left to right, from A, inside 
the coax« to the shorted end. There's anoth- 
er quarter-cycle delay as the wave passes 
back from right to left inside the coax and 
emerges on the shield at B . Add up the delays 
and you get a total time delay of one-half 
cycle, or 180°. 

RF energy can also readily turn comers if a 
lower impedance beckons. Thus, we further 
expect the RF wave to continue travelling to 
the right* along the outside of the coaxial 
shield, arrivmg at C The setup shown io 
Figure 3 replaces that in Figure L In Figure 
3, the stubs are horizontal. They pjerform the 
desired phase reversal while providing part 
of the added half-wave radiators with the 
outsides of their shields. You need only add 
enough wire at the ends to complete the CO- 
COA-3 radiaton, (See construction details 
below.) 

Six-Elexneiit Phased Array (COCO A-6) 

For a given power IcvcK the current at the 
feedpoinl of the COCOA-3 radiator is lower 
than that for the simple dipole radiator, so the 
input resistance in this case is higher. Add a 
toroidal transformer at the CO- 
COA-3 input to decrease this value 
to 50Q. If possible, put the match- 
ing transformer at the top of the 
mast that supports the radiator cen- 
ter. 

Once the impedance \s matched 
to 50Q, you can excite the two CO- 
COA-3 radiators. The phasing can 
be controlled by a switching net- 
work, as in the 2-element phased 
array. Figure 4 shows the CO- 
COA-6 arrangement with nominal 
lengths for 3,955 MHz, I measured 
these lengths electrically, using a 
ttoise bridge to assure precise 
matching. 

Keep 'em High 

Each COCOA-3 radiator is ap- 
proximately 354 feel long (noise- 
bridge measurements determine 
the exact dimensions). For lower 
frequency bands, it*s very impor* 
tarn to place all radiating elements 
as high as possible above ground, 
since ground penetration greatly 
reduces radiation efficiency. If 
possible, support all three CO- 
COA-3 elements no less than 40 



•t 



24 73 AmafBur Radio • AugiJsU9S9 



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73 AmatBur Radio • August, 1989 25 



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Figure 4, The COCOA'6. a 6-eiemem phased array. "X" is the direcuon-swiiching manifold. Lengths shown are 
nominal values far 3.955 MHz, 



feet above ground. They work best at one 
quarter-wavelength (about 60 feet) above 
ground. 

The center ma^ts at W20ZH proved practi- 
cal over the years. I briefly describe their 
arrangement here. (Sec Reference 1 for more 
details.) Each mast is made from three 20- 
foot lengths of 2- inch outer diameter (o.d.) 
aluminum irrigation pipe, spliced end-to- 
end. Place die bottom half of each mast a>a3c- 
ially inside a 30- foot length of 3-inch o.d. 
pipe for added strength. Use quarter-inch 
crossed bolts to complete the mast assembly. 
Pivot the assembly on a 1-foot high, 2-inch 
diameter post, anchored in concrete in the 
ground. 

The aluminum *s light weight md the stiff- 
ening effea of the double pipe make for easy 
erection. After erection, bolt the masts to the 
roof structure at about 18 feel above the 
ground, and guy wire them in four directions 
at about 40 feet, as well as at the top. The 
center radiator wires guy the mast at the top in 
two of the four directions. 

Pass the coaxial feedltnc (RG-213/U) up 
through Ibe masts to the top insulator assem- 
bly. This assembly is a 6-inch length of 
capped PVC pipe, I-inch i.d., that contains a 
balun transformer. Firmly anchor the feed- 
line hcre» and pot the assembly in automotive 
grade epoxy. 

Phas^ Reversing Stubs 

The center radiators extend about 59 feet to 
either side of the center masts. Use seven 
strands of #22 copper-clad wire. After final 
measurements, paint them with polyureihane 
varnish to resist rust. Type RG-8 Mini-Foam 
coax works well here because it*s light and 
convenient to handle. Make sure the coax 
terminals are mechnnically secure, and that 
you've put a good moisture seal on them. 

26 73 Amateur Radio • August, 1989 



Figure 5 shows this in detail, Seal both ends 
of the coax after trimming it to precisely one 
quarter- wavelength. The spade lugs are con- 
venient for disconnecting the end sections of 
the COCOA-3 during resonance measure- 
ments. 

Measurements and Adjustments — 
COCOA-6 

You need to adjust the electrical length of 

each phase reversing stub on the ground, 
before assembly, using a noise bridge. The 
impedance-transforming properties of a 
quarter-wavelength of coax are such that^ if 
the far end is an open circuh, the impedance 
at the near end is essentially zero. Connect 
the noise bridge with short leads to one end of 
a 47'foot length of RG*8 Mini-Foam coax, 
and trim the other end until the null corre- 
sponds precisely lo the desired frequency. In 
this article, I use 3*955 MHz. Then assemble 
and seal both ends, a^ Figure 5 shows. 

Let's assume we are adjusting the full 6-el- 
ement array (The procedure for adjusting a 
single, 3-elemeni array is identical, except 
yoii don't have to consider the second fed 
radiator.) You adjust the three elements of the 
COCOA-3 sequentially by noise bridge mea- 
suremem, beginning with the center element. 
Before measuring the antennas, trim the two 
feedlines so that the electrical length of each 
is an integral multiple of one half- wavelength 
(in the coax) for the frequency used. This 
assures that the impedance of the antenna 
fcedpoint is measured accurately by the noise 
bridge. In my case, each feedline is two half- 
wavelengths long at 3.955 MHz, measured 
and trimmed in a like way as for the phase 
reversing stubs. 

Again refer to Figure 4, To adjust the an- 
tennas, open the spade lugs (which connect 
the end elements to the center elements of 



both COC0A-3s) at A, 
A \ C and C\ and puU 
the antennas up to their 
final positions. To al- 
low for the mutual 
impedance effect be- 
tween the two anten- 
nas, terminate the 
feedpoint of the non- 
adjusted * 'antenna** 
widia50O, I Wan car- 
bon resistor. The noise 
bridge null now mea- 
sures the input resis- 
tance as approximately 
son at the resonant fre- 
quency of this dipole 
antenna. Adjust the 
lengths of the wires 
equally, at points A and 
C until you reach the 
desired frequency. 
Then shift the resistor 
to Ehe newly-adjusted 
antenna and trim the 
second dipole to reso- 
nance in the same man- 
ner. These two dtpoles 
now make up a 2-ele- 
mcm phased array. The 
gain, compared to a dipole. is approximately 
4 dB. The front -to-back ratio varies, typicaMy 
from 3 dB to as much as 30 dB, depending 
upon propagation conditions. 

End Element Radiator Adjustment 

You can still terminate the fe^line of the 
antenna you are not adjusting with a SOQ 
resistor^ even though the feedpoint rc^istafice 
is now somewhat higher. Connect the 
spade lug at A on the side which goes to the 
feedline's center conductor. Point C, on the 
side going to the shield « remains open during 
the resonating of the opposite end element- 
Connect the noise bridge at the input end 
of the feedline to see the resonance of the 
l-^lemeni (COCOA-2) antenna— two half- 
waves in phase. Trim the element at B 
until you get the desired resonant frequency. 
The measured input resistance will be 
somewhat higher than for the dipole » about 
60-70Q. Next, shift the resistive termina* 
tion to the feedline of the COCOA-2 just 
adjustexl, and adjust the resonance of the 
other antenna in a similar manner by trim- 
ming at B '. Check and readjust, if necessary, 
the first antenna. 

The two antennas just adjusted make up a 
4-element phased array, the COCOAS. 
There's a slight mismatch because the input 
resistances are no longer 50n. This results in 
a small phasing error, but you can compen- 
sate for this by using two toroidal matching 
transformers (see below and Figure 9}- 

Adjust the remaining two elements, C-D 
and C^-D\ in the same fashion. The spade 
lugs at A and A * remain connected, and those 
at Cand C will now be connected* Trim the 
ends at D and D* to resonate the two CO- 
COA-3 radiators, just as the COCOA-2 an- 
tennas were adjusted. Here^ the input resis- 
tance will be from IOO-i20D, so the 

tontinued on p. 54 



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73 Amateur Radfo • August^ 19S9 27 



Number 9 on your Feedback card 



73 Re vie w 



by Alan C Merrill WIFYR 



Ameritron AL-80A 
Linear Amp 

A reliable IkWamp at a bargain price. 



Amsrilron. Inc. 

2375 Dorf Street 

Toledo OH 43607 

Phonet (601) 323^9715 

Technical Inquiries: (419) 531-3024 

Price Class: $995 



Ever tried to work a rare DX statk^n. 
and have him lell you that he just 
couldn'l pull you out of the mud? Then 
Ihe big guns opened up, and you were 
gone. 

Ever tried to get a ptece of priority 
traffic through when the receiving sta- 
tion couldn't pull you out of the slop, 
and there was no one around to relay? 

Ever try to call the net up when only 
half the members could hear you? 

Ever gel on a frequency during a con- 
test and after a few nice contacts, have 
another station "steal" your spot be- 
cause he didn*t even know you were 
there? 

Ever get on 75 after a solar flare and 
try to keep your schedule with the 
gang, only to realize that you are just 
barety hearing them, but not vica*ver* 
sa? 

If sOp sounds like you need an amp! 

Many times, fn a marginal copy situa- 
tion, the extra 1 dB of a linear amplifier 
will make all the difference in the world. 
My hat is off to the QRP gang. I greatly 
admire those devotees, but there are 
times when an amp may wefl be the 
answer to a ham*s prayers. To be legal 
as welt as courteous, I always try to 
make it with the exciter alone. Bui It is 
also nice to be able to hit a switch and 
add another 10 dB to your signal. So 
often in handling traffic I have been 
told, "Sorry. Alan, you are not strong 
enough for me to copy traffic/' After 
hitting the switch, it changes to "Loud 
and clear— send your traffic/' It cer- 
tainly beats QSP. 




Photo A, The front panel of the ALSOA, showing controis, 
itluminated multimeter, arni grid meter. 




Phoio B. Rear panel showing the SO-239 connectors, phono 
plug connectors for^EiAY, alcout, and i2 volts. Also v/s/bfe 
are the ALC adjustment pot and dual fuses on the AC tine. 



Desirable Features In an Amplifier 

There are a number of nice HF linear ampli- 
fiers available today, both in kit form and fully 
built, and they range in price from a low of 
$600 to a high of better than S40O0. 

I was looking for an amp that had a re- 
spectable output, not necessarily the legal 
limit; woutd cover all bands mcluding WARC; 
was well-constructed; used a tried and true 
relatively inexpensive tube or tubes; had a 
relatively small footprint; had a provision for 
QSK (full break'in) that would work on 

28 73 Amateur Radio • August, 1989 



AMTOR; used a time-proven desrgn; and 
lastly, would not cost me the proverbial arm 
and a leg. 

The more I looked, Ihe better 1 liked what f 
saw in the Ameritron AL~&OA. It met all my 
criteria* and then some. Although the AL-60A 
!s not a QSK machine in its basic form. Amer- 
itron makes a Pin 5 board you can add in the 
field. It switches fast enough for AMTOR. It all 
looked good, so I counted out a bit of the coin 
of the realm, and bought one. It was a good 
choice! 



AL-aOA Specifications 

The AL*80A is the second step up, 
power-wise, in the Ameritron series of 
amps. The smallest one, the AL-e4, is a 
400 Watt CW. 600 Watt PEP SSB unit. 
The AL-80A is a nicely designed am- 
plifier, using a tried and true single 3- 
SDOZ high mu triode, running in class 
A82 grounded grid. The 3-500Z is not a 
cheap tube, but on the other hand, if 
you ever have to replace one, it will not 
break the bank. Ameritron claims an 
RF output of 1 000 Watts PEP SS8 and 
850 Watts CW. My experience with the 
amp showed that both output figures 
were easily reached, with Bird and 
Heath wattmeters to tell the story. 1 run 
a lot of RTTY, with key down for 5 to 10 
minutes at a time. I found that if I kept 
the output to about 500 Watts in this 
mode, the amplifier showed no signs of 
overheating. 

The claimed driving power is typical- 
ly 85 Watts, Both my rigs (with outputs 
of about 100 Walts) drove the AL-80A 
to full power on all bands. 

You can configure the amp for 120 or 
240 volts AC by using jumpers on a 
terminal strip. An optional multi-voltage 
transformer is available, allowing for 
oddball voltages, such as 110. 115. 
230, or 235. The filament supply has 
inrush current limiting to insure maxi- 
mum tube life. A very efficient, quiet 
cooling system keeps the tube cool 
even dunng conUnuous operation. 

The amp Is shipped with the tube in a 

separate container, as it should be. In 

opening things up to insert the tube and 

to check for the proper voltage setting, I was 

impressed again with the good construction, 

steel chassis, clean layout, and the obvious 

high quality of the parts. Everything is well- 

shielded and bypassed to help with RFI and 

TVI problems. The power transformer, with a 

core of hypersil steel laminations, weighs 

about 22 pounds. The complete unit weighs 

aboul 50 pounds, with shipping weight a few 

more pounds. Its footprint is 8^4 inches high, 

14^4 inches wide, and 15 inches deep. 

Frequency coverage is 160 through 10, 







S4I3 



SYMBOL OF ENCrNEERING INTEGRITY. , .QUALITY 
WORKMANSHIP. , .RELIABLE LONG-LIFE PERFORMANCE 




AL-80A LINEAR AMPLIFIER 

The ALSO A wm provide a signal output that is within 1/2 "S"unH 
of the slgnai output 0f the most expensive ampimer on the 
matkef—and at much tower cost 

~f^e Amentron AL-80A combines tne economical 3-5002 with a 
heovv duty tank circuit to actiieve nearly 70% efficiency from 160 
to 15 meters. It has wrde frequency coverage for MARS and other 
authorized servtces Typscol drive is 65 wotts to give over lOOO watts 
PEP SS6 and 850 watts CW RF output A new Pi-L output circuit for 

80 and 160 gives full band coverage and excepttonotiy srriooth 

tuning. 

Size: 15y2"D. X 14"W x 8"H. Wgt 52 lbs 




AL 1200 LINEAR AMPLIFIER 

3CX1200 TUBI 

Full legal output with lOO watts drive 



AL-1500 LINEAR AMPLIFIER 

8S77TUBE 

Full legol output wit^ 65 wotts drtve 

The cooling system m both amplifiers keeps the 
tube safely below the manufacturers ratings even 
when operating at 1500 wotts output with a steady 

corner The filament supply has onrush current flm^t^ng 
to insure rmoximum tube life. 

Size 18V2"D X 17" W. x lO 'H Wgt 77 lbs 




AL-a4 

LINEAR 

AMPLIFIER 




The Amerltron Ai*i4 is an economicol amplifier using four 
6MJ6 tubes to develop 40O watts output on C W and 600 
watts PEP on SSB from 160 through 15 meters Dnve required 
^s 70 w typical. lOO w max The passive rnput network 
presents a low SWR input to the exciter Power input is 900 
watts. The AL-84 is an excellent back-up- portable or 
beginner's amplifier, 



SJze nV2"W X 6"H x }2W'D Wgt 2A ib^ 



ATR-15 TUNER 

The Amerltron ATR'TS is a 

1500 watt 'T- network tuner 
that covers 13 through 30 MHz 
in lO dedicated bands Handles 
full fegal power on oil omateur 
bonds above 18 MHz. 



Fwe outputs ore selected from o heavy duty antenna switch 
ollowir^g the rapid choice of three coaxial lir>es. one single 
terminal feed or o boianced output An interrxif baiun pro- 
vides 1 1 or 41 ratios (user selectable) on the boianced output 
terminals. 

A peak reading wattmeter and SWR bridge is standard in the 
ATR-15 It accurately reads envelope powers up to 2KW 

Size 6"H X 13Vi W X 16"D Wot 14 lbs 



RCS-4 

FOR CONVENIENT 

INSTALLATION 

No control cable required 
Selects one of four antennas, 
VSWR: under 1 1 to 1 fronn 18 to 
30 MHz 

Impedance: SO ohinns 
Power copcibility: 1500 watts 
average, 25O0 watts PEP 
maximunn 



Remote COAX Switches 




RCS-8V 

FOR SPECIAL 

APPLICATIONS 

Selects up to five antennas. 

Loss at ISO MHz; less than .1 dB. 

VSWR: under 12 to 1 DC to 250 

MHz, 

Impedance: 50 ohms. 

Power capabllltY: 5 kW belovw 

30 MHz. 1 kW at 150 MHz 



Available at vour dealer. Send for a catatou of the eomplefe AMERITRON line. 




2375 Dorr Street • Toledo, OH 43607 
For more information: (601) 323-9715 • Technical inquiries: (419) 531-3024 



J 



emeu. 314 OM READCIR SEirVieE CAITD 



inctuding the WARC bands and most MARS 
frequencies. To enable the 10 and 12 meter 
bands, you have lo make a very simple modifi- 
cation. All the parts are Ihere; you just have 
to enable them. To obtain the informatron, 
write a note to the factory with a copy of your 
license, or talk to someone else who owns 
one. 

The tuned input circuit (a necessity with 
most solid state exciters) is an adjustable Pi* 
network, and the output circuit is a Pi-L net- 
work, with harmonic suppresston. 

The claimed etticiency on CW/SSB is better 
than 66%. Spot checks on CW gave me be- 
tween 67% and 70%. 

Front Panel 

TTie AL-80A has two illuminated meters, the 
left*hand meter being a multimeter which 
shows high voltage, plate current, RF output 
and ALC voltage, depending upon the switch 
position. The right-hand meter is only for grid 
current, and allows you lo monitor this impor- 
tant parameter continuousty. 

Two rocker switches control POWEPyoFF and 
Crt^ERATE/STANDBY. In the standby position, the 
amp is out of line» and the eMclter is operating 
straight through. Incidentally, the 3-500Z tube 
is ao "inslant heating" type, so there is no 
long wait for the tube to come up to operating 
temperature. (I hate to do that to a tube, 
though!) 

The band switch has 160, 80, 40, 20, 
and 15 meter positions. The unmarked 
position to the right of 15 is the 10 meter 
position. It will work if you have enabled 
the 10 meter band, as discussed previ- 
ously. Go to the nearest listed band on 
the band switch lo reach the WARC 
bands. 

Both the LOAD and plate controls 
have reduction gears, and provide very 
smooth tuning, There is a small red 
pilot light to indicate when the unit es in 
transmit. The controls are nicely laid 
out and easy lo operate, even with my 
fat fingers and big hands. 



either voltage setting, you need to take 
the case off. While the case is off, place 
the tube in tts socket. There is an interlock 
switch for protection from high voltage if 
the cover is off and the amp gets plugged in 
and turned on. Voltages in there are high 
enough to be FATAL— don't bypass the inter- 
lock! 



'7 was able to use 

the WARC bands with 

just about full power 

by using the closest 

'oid* band position. '' 



6e sure to have a good earth ground. Also, 
install a good heavy wire or braid connection 
between the exciter, the antenna tuner (if you 
use one), and the amplifier. I hooked up every- 
thing with '^nnch copper braid, and kept the 
ALC lead and the relay lead as short as possi- 
ble. I used shielded wire, as the instruction 
book suggested, tor the two leads. 

The instruction book gives you a very brief 
outline of tune-up procedures. Tune up for the 



Rear Panel 

On the rear panel, towards the lop^ 
are two SO-239 connectors for the RF 
in and RF out. The remaining connec- 
tors are phono jacks. The next one 
down Is for the relay, and goes to a 
normally open contact In your exciter. 
Unlike some of the older amplifiers with 
100 votts DC. this amp only uses 12 
volts at 1 0O mA to switch to transmit All 
solid state rigs that I know of wilt handle 
that voltage nicely. 

Next is the ALC jack, to supply ALC 
vottage back to the exciter. Below that 
is the ALC pot for controlling the ALC 
voltage. Below that, and at the bottom, 
is yet another jack that supplies 12 volts 
DC at 100 mA for any use you may 
have. There is a good heavy lug with a 
wing not for the earth ground, and of 
course two fuses and the AC line cord. 

Hookup and Operation 

To configure the jumper block for 

30 73 Amateur Radio • August. 1989 




Photo C. TheRFcompartmenl showing the Pt-L Network, the 
3'500Z with fan just behind it, and the tuned input circuit 
which is fust behind the fnjnt panel The layout is clean. 




Photo D. The power supply compaftment^ Note the hypersH 
transformer, filter caps, and diodes. The hohzontat circuit 
board aixive the transformer is the optional Pin 5 QSK board. 



80A is typical — you start with low drive ar>d 

keep adjusting the plate and load controls for 
resonance ai the operating frequency as you 
increase the drive. Keep the grid meter below 
200 mA during operation. I made some notes 
as I went along, and marked the plate dial to 
make it easier to rebcate the spot again. I 
tuned the unit up into a dummy antenna first 
before putting it on the air; With the availability 
of inexper^sive dummy antennas, there is ab- 
solutely no need to do any of your preliminary 
testing on the air. 

In order to get full output I needed to adjust 
the ALC pot on the rear of the amplifier, I used 
my station monitor, which happens to be one 
of the Heath SB series, to look at the RF envel* 
ope and to check for clipping as I set the ALC 
control. The instruction manual does not give 
you much information on this procedure, but 
most of the recent amateur handbooks have a 
detailed section on amplifier tune-up. After \ 
finished the preliminary tests on the dummy 
load. I tried a couple of critical on the arr 
checks* with a few of my hypercritical friends. 
All the reports were gratifying! I suspect most 
of the 100 Watt exciters probably will not give 
you much problem with clipping when used to 
dhve the AL-60A, assuming everything is cor- 
rectly tuned. 

The band switch only covers the six "ofd" 
bands. \ was able to use the WARC bands with 
just about full power by using the 
closest "old" band position. For ex- 
ample, the 12 meter band will work 
in the 10 meter position, and the 17 
meter band will work in the 15 meter 
position. 



Final CommenU 

I wish the instruction manual were 
more detailed. The basics are alt there, 
with parts list and schematics, but 
there could be more detail in. for exam- 
ple, the tuning procedures and ALC ad- 
justment. Perhaps I am just spoiled 
with the Heath type manual* And 
speaking of Heath, their SB-1000 HF 
linear amplifier, available in kit form, 
looks suspiciously like the AL-SOA! 
Who knows? 

One other minor problem was the pq 
position on the multimeter. It it is sup- 
posed to show peak power out in Watts. 
Like many built-in power meters^ it only 
shows a rough approximation of power 
which does not correlate well with an 
external meter known to be accurate. 
As long as the reading is not taken as 
gospel, you can use it as a relative indi- 
cator. 

Having used the amp for several 
months now. I can report that it per* 
forms very well, with very nice reports. 
There has been no hint of instability 
even when the SWR was a bit higher 
than it should have been. It is quiet, 
reliable, and easy to tune. I obtained a 
Pin 5 QSK board for the uniL which 1 will 
try it out for a few months before report* 
ing on it. All in alL (he AL-SOA was just 
what I was looking tor, and 1 am certairv 
ly pleased with it. 



73 Review 



byEdClegg W3LOY 



Uno, Dos, Cuatro 



Introduction to the 
Numbers Stations 



Tiare Publishing 
Lake Geneva, W( 531 47. (414) 248^845 

Price Cfass: $15 



Has there ever been a ham who didn*i experi- 
ence a surge tif excite men! upon hearing a 
my^iterious signal thai sounded J ike a tiandestinc 
nie&<;age? Don't we all have a little "Mission Im- 
|X>ssibie*' or *'dOT' in ourbiood? 

With the advent of ham iranscefvers thai include 
continuoij.s receiving coverage From VLF to 30 
MHy . ^tnne of us have become shore wave listeners 
as a hobby within our hobby. More hams are into 
SWLing than will admit it. 

fihrouded in M>^ler>- 

According to the Publishers note, '*Uno, Dos, 
Quatro' ' was written by an e^t-raemberof the intel- 
Itgcnce community. Though the book offers only 
obscure info on him, the Preface states that "'Ha- 
vana Moon" has appeared in print e be where for 
several years. The note that he was quoted fre- 
quenlly in the Ncwurk f NJ) news Radio Club testi- 
fies to his tenure since that periodical ceased lo 
exist quite a few years ago. 

Real Page-Turner 
My curiosity was mslantlv piqued: midway 



through the first chapter I started tuning my TS-930 
to frequencies where it had never been to before 
lotiking and listening for signals of the nature de^ 
jicribed by Seiior Mtnin. 

What is the nature of Moon's mysterious sig- 
nals? Simply, groups of four or five digit numbers 
transmitted in a well-organii^ed manner, and in 
various languages. He reports that many are deliv- 
ered in English spoken with various alien accents, 
while some are in Spanish spoken w iih English or 
German accents. The author does not hint lo the 
location of these signal sources in most cases, but 
there are notable except ions « includinx wifhin the 
US. Such US QTHs include Vent Hill. Virginia, a 
publicly known monitoring post for the goverrt- 
mcnt. and Tequcsu. Florida, a unique government 
outpost which includes a LORAN station and mis- 
sile tracking system. Moon also suggests that some 
numbers stations have questionable allegiance to 
the US. alluding to such transmissions from Cuba. 
Don't count on those transmissions coming from 
Guantanamo Bay! 

The subject matter was so fascinating that I could 
endure the disorganize presentation Some chap- 



Number to t>n ycMir Fe«dt>ack card 

ters consist principally of lists of Frequencies 

where one has a good chance of hearing these 
mysterious transmissioiK, Jn later chapters, 
however. Moon tells us that previously listed 
frequencies may not be currently active. Tbeiie 
is little or no indication in the text that some of 
the * 'high probability of intercept frequencies" 
are daytime or nighttime predictions, except for 
the ane i experienced and was able to confirm 
on two separate instance x! In this case, the 
attthor accurately forecasted not only the day of 
the week and ihe time of the day » but also the 
a[^)areni source in Florida- I discovered ihai 
the lime, frequency, and apparent source were 
all accurate? That experience alone was enough 
to justify the purchase and gel me hooked* 

The book is a paperback in large sheet format 
with 90 pages including about a dozen pages 
thai were cither afterthoughts or later edition 
supplements. These include a listing of other 
related publications by the publisher and ex- 
cerpts from Mtmitoring Times as well as Popu- 
lar Communi tut ions. 

Hre Up The SW Receiver 

Give a listen sometime to 11,565 kHz at 

2000Z on Saturdays, and you may well be in 
for a pleasant surprise. Now Vm in the market 
for a mu It i- frequency, multi-channel, long- 
long-long playing tape recorder so that I don't 
miss out on any of these mysterious signals. 

This book has certainly whetted my appetite. 
] look forward to seeing a guide to possible 
meanings of these codes! Anyone interested 
in forming a numbers stations monitoring 
net? 



ASSOCIATED RADIO 

801 2 CONSER BOX 4327 
OVERLAND PARK. KANSAS 66204 



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73 Amateur Radio • August, 1989 31 



Numlffir 1 1 <m ymir F&^€imtk card 



by Larry R. Antonuk WB9RRT 



73 Review 



Ramsey COM 

The most features for the money in 
communications service monitors. 




Ramsey Electronics. Inc, 

2575 Baird Road 

Penfleld, NV 14526 

TeJ: (716)586-3950 

Price Class: $2500 



III just bought a $2500 service moni- 
I lor!" Drop tin at statement into fm> 

fite ham conversatior*, and you're guaran- 
teed one of two resposas: 

A. "Wowf" 

B. "What's a service monitor??" 

From Many Boxes to One 

First, the answer to *'B." A communica- 
tions service monrtor is a tool used by 
anyone m the two-way radio business, or 
anywhere that precise measurement of 
radio parameters is needed, tn the days 
before synthesizers, pha&e^locked loops, 
and memory scan, back when they even 
used tubes, technicians needed to carry sev- 
eraf pieces of equipment. 

Rrst, he needed a wattmeter for indicating 
forward and reflected power. Next^ he needed 
a frequency meter to give tiim an idea of 
whether or not this power was on the correct 
frequency. Once he was assured of that, he 
could pull out his modulation meter to check 
his transmitter's deviation. If the deviation ts 
within the specifications, he loads all of the 
equipment into the van and hauls out the sig- 
nal generator to measure the receiver's sensi- 
tivity, He could then modulate the signal gen- 
erator with an audio tone generator to check 
the audio circuits, A CTCSS generator would 
let him check the private line (PL) operation. 
All in aJt» a wen-equipped technician couid 
easily have half a dozen boxes with him at all 
limes- Imagine having to hike up a mountain 
while trying to decide which equipment to haul 
alongl 

A few years back, technology advanced to 
the point where it became feasible to roll all of 
these pieces of equipment into one box. 
These units were called system analyzers, 
communications monitors, etc., but the term 
"service monitor/* or simply "monitor," 
stuck. Today's service monitors combine all of 
the above features, with the more advanced 
units performing spectrum analysis, tone de- 
coding, and many specialized functions. The 
only problem with service monitors is the 
price. 

Obviously, a unit that can take the place of 
six pieces of test equipment has to cost seven 
times as much as the most expensive piece! 
Indeed, the price of the average service moni- 
tor IS around eight thousand dollars, with 
some deluxe models clearing the twenty thou- 
sand mark. 

Now microprocessor technology has devel- 
oped to the point where Ramsey Bectronics 

32 73 Amateur Radio • August. 1989 




The Rams&y COM~3 Service Monitor packs a lot 
loois into a singl& uaiL 

can offer a full-featured communications ser- 
vice monitor for $2495. The Ramsey COM-3 
measures frequency, modulation, and recerv- 
er sensitivity— all the normal service monitor 
functions, tn addition, the unit offers several 
features not found on units costing three times 
as much: a ten channel memory, repeater off- 
set buttons, audio frequency counter, RF fre- 
quency counter, CTCSS lone generator, and 
buitt-in battery pack. 

How for the Wow 

The COf^-3 package measured 1 2" x 5-5" x 
14" and weighed a mere 13 pounds. The con- 
trols on the front panel are the onnoff/volume, 
squelch, and RF level controls. You access all 
other operating functions, such as generator 
attenuation, in addition to basic numeric in- 
put, with the membrane keypad, which covers 
the entire face of the unit. 

As far as basic sen/ice monitor functions. 
the COM-3 has the same capabilities most 
monitors have. You can generate or monitor 
frequencies from 100 kHz to 999.9999 MHz. 
The generator has a range of 0.1 pV to 1 0,000 
pV, and can be modulated by an internat test 
tone or CTCSS tone. 

The unit measures modulation in two 
ranges, 1.5 and 7.0 kHz, on a 2G-segment 
L£D bargraph. In addition to these functions, 
however, the COM-3 performs quite a few 
tricks of its own. 

Once you get used lo the keypad frequency 
entry system, you'll want to store often-used 
frequencies In one of the ten memory posi- 
tions. Rather than simply storing frequencies, 
these positions store complete operating 
modes. For instance, memory one could gen- 
erate 1 47,375, modulated with 1 kHz tone and 
1 23.0 Hz PL tone. Hit memory two» and youVe 
monitoring 448.600 MHz, AM mode, counting 
PL tone. All at the push of two buttons. If you 



of 



don't know the fr^ency. simply use the 
built-in frequency counter. Once you 
count the frequency, put that freq in the 
monitor and enter the Audio Freq Count 
mode to decode any CTCSS tones. 

Service techs will especially appreciate 
the progfammable plus or minus offset 
buttons, and an up/down 5 kHz at-a-time 
function. The first feature makes it easy to 
switch back and forth tietween a transmit 
frequency and the associated receiver fre- 
quency of a repeater pair, and the second 
feature acts like a VFO. letting the opera- 
tor "tune around" to check the bandpass 
of a receiver, etc. 
The COM-3 cannot measure RF power, but 
it can protect itself from it. Once the unit sens- 
es input power of more than 500 mW, it switcfi- 
es the input to a BNC connector on the back 
paneL (You previously attached a dummy 
load to this port, of course, anticipating ttmt 
you were going to goof and key a radio into 
your brand new monitor.] 

Drawbacks 

The COM-3 has very llttie in the way of RF 
shielding. Once the cover is removed from 
the unit^ the large main board sits relatively 
unprotected on the bottom of the case. It 
doesn't have the heavy shielding, bypass- 
ing, and fingerstock seen on some monitors. 
While this might present a problem at a com- 
ntercial broadcast station or a crowded re- 
peater site, most hams and radio technicians 
will firKJ the RF immunity of the monitor mor« 
than adequate. 

Speaking of broadcast stations, the FM 
monitor mode is designed only for 5 kHz sys- 
tems — 75 kHz commercial systems can't be 
measured. One final point concerns the lack 
of an "image" switch to identify "birdies/* 
Like all monitors, the COM-3 produces birdies 
(as do all monitoi^), but we have no way to 
distinguish birdies and image frequencies 
fnomthe real thing. 

Conclusions 

All in all, the Ramsey COM-3 is an excep- 
tional instrument. Whether purchased for a 
two-way shop, ham club, or for a ham making 
the transition to a service business, the 
CQM-3 represents a lot of equipment for 
the dollar. With the addition of the optional 
case ($90) and the carrying handle/front cover 
($30), the unit t)ecomes a go-anywhere ser- 
vice tool. There's really only one word for it 
"Wowl" 



ii§ §m§ii 9 



uniden 

$12, , 

Scanner Sale 

Uniden Corporation of Amerfca lias pur* 
chased the consumer products line of Re- 
gency Electronics Inc. for $12,000,000. To 
celebrate this purchase, we're having our 
largest scanner sale in history! Use the 
coupon in thisad for big savings. Hurry.. .offer 
ends September 30, 1989. 

• • # MONEY SAVIHG COUf^Hi, • ic 

QBt speciai savings on the scanners 
Ifsi^in this coupon^ Thisuoupon must 
be inciuded with your pr&patd order. 
Credit cards, personai checks andquao- 
tity discounts ar© ^Kciuded trom this 
offer Otter vattdoni/on prepaid orders 
mailed dfrectfy to CommunicatfOns f tec- 
tronios inc., P.O. Box 1045- D&pt UN (6. 
Ann Arbor Michigan 48W5-W45U.S.A 
Coupon expires September 30, i939. 
Coupon may not be us&din confunction 
with any other offer from CEt. Coupon 
may be photocopied. Add $11.00 for 
shipping in the continentaf U.S. A 

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De a very fo r th is ne w produc t iB schedu fed to f Jun a 1 9 89. 
The newFres/denr HH26O0 Mobile 10 Meter Trans- 
ceiver is similar to the Uniden HR2510 but now has 
repeater offsets (100 KHz.) and CTCSS encode. 



BC760XLT 

eoo MHz. 
mobile scanner 

SPECIALl 




irit^ Facsimile MacMfio« 3 Phonos if it if 

FAX3300*T Pactei Fa ?f machine witin pihone . , . . $1 ,099.95 
)CE750-T Uniden Cordless Phone wilh speaker ,., , , $99-95 

XE660*T Uniden Ccrdie&s Phone $79.95 

XE300-T Uniden Cordless Phone $69.95 

iririr EMtondod Sor¥ica ConiraQi iti^ir 

If you purchase a scanner, CB, radar detector or cordless 
phone from any store in the US, of Canada within rtie last 30 
days, you can get yp 10 three years of extended service 
contract from Warrantech. This service ejttension plan begins 
Sft0f the manufacturer's warranty ejcpires. Warrantech wiH 
perform all necessary labor and will not charge ior return 
shipping. Extended service contracts are not retundabte and 
apply only to th e ori gi n al pu re ha se f, A two year ext e nded con- 
tract on a mobile or base scanrier is $29.99 and three years is 
$39.99. For handheld scanners, 2 years (S $5999 and 3 
years is S79. 99- For radar detectors, two years is S29, 99, For 
CB radios. 2 years is $39.99. Forcordless phones, 3 years is 
S34.99- Order your extended service contract today. 

OTHER RADiOS AMD ACCESSORIMS 

BCS5XVT-T Bearcat 10 channel scanner ...St 14.95 

BC70?(I,T-T Be^rc^tS 20 channel scanner, , , ST69.9S 

BCI 7 5XLT-T Sear caf 16 channel Scanner ,.....-$156.95 

R2060-T R&gencySO channel scanner,,*^.- $149.93 

TS2-T RegerTcy 75 channel scanner $259. 95 

UC1 02-T Regency VH F 2 ch. 1 Watt traneceiver, ., $ 11 4.95 

BPS5-T Regency II 6 amp reg. power supply. $1 79.95 

BP205-T Ni Cad batt. pack for BC200/BC1 OCXLT , . . $49.95 
B6-T 1.2 VM Ni^Cad batteries (set of eight).., :,...$ 17.95 

FBE'T Frequency Directory for Eastern U.S.A $14.95 

FBW'T Freouency Directory for Western U.S.A- . . . . S14.95 

RFD1 -T Great Lakes Frequency Directory $14.95 

RFD2'T New England Frequency Directorv* $1 4.95 

RFP3-T Mid Atlantic Frequency Directory . . , $1 4.95 

HFI>4-T Southeast Frequency Directory $i 4.95 

RFD5-T N.W A Northern Plains Frequency Dir. . . . , Si 4.95 

ASD-T Airplane Scanner Directory E14.95 

SRF-T Survival Radio Frequency Directory $1 4,95 

TSG-T "Top Secret Registry ot U.S. Govt. Freq. . . . S 14.95 

TTC-T Tune ih Oh telephone c^lls .....,.,, Si 4.95- 

CBH-T Big CB Handbook/ AM/FM/Freeband. . .... $14.95 

TIC-T Techniques for Intercepting CorT>nrbunicati.ons ..314.95 

RRF'T RaiJroad frequency directory Si 4.95 

EEC-T Embassy S. Espionage Communications. .. .$14.95 
CJE-T Covert Inteilrgence, E^ecJ. Eavesdropping .. .$14.95 
MFFT Mid*est Federal Frequency directory ..... $14.95 

A60-T Magnet mount mobile scanner antenna $3 5. 95 

A70-T Base Station scanner antenna $35.95 

A1 300*T 25 MHi.-l 3 QHt Diacone antenna . . $109 95 

USAMM-T Mag mount VHF ant VV/ 12 cable $39,95 

USAK*T%" hole mount VHF ant. -m/ 1 7' cable $35.95 

Add $4.00 shipping for al4 accessories ordered at the same time. 
Add $1 1 .00 shipping per radio and S4.00 par antenna. 

BUY WITH CONFIDENCE 

To ffmi tho fomiaiti daUvery from CMi of any scanner, 
send or phone your order diirectiy to our Scanner 
Distribution Center!" Mictiigan residents please add 4% 
sales tax or supply your tax ID. number. Written pur- 
ctiase orders are accepted from approved government 
agencies and most weti rated firms at a 10% surcharge 
tor net 10 billing. AH sales are subiect to avaiiabiiitv, 
acceptance ar^d veritic^at^on. All sales on accessories 
are final, Prices, terms and specifications are subject to 
ctiange wwithout notice. Ali prices are in U. S. dollars. Out 
Of stock items will be piaced on backorder automatically 
unless CEI is instructed differently A $5.00 additional 
handli^ng fee will be charged tor all orders with a 
merchandise total under $50.00. Shipments are F.O.B. 
CEI v\^ a rehouse in Ann Arbor, Michigan. No COD's, 
Most ftems listed Inave a manufacturei^s warranty. Free 
copies of warranties on these products are available 
by 'writing to CEI, Non-certified cliecks require bank 
clearance. Not responsible for typographical errors. 

Mail orders to: Communications Electrcn- 
icsr Box 1045, Artn Arbor, Michigan 46106 
U.S.A.AddS1 1.00 per sea nnerf or U. P. S. ground 
shipping and handling in the continental U.S,A. 
For Canada, Puerto Rico, Hawaii, Alaska, or 
APO/FPO delivery, shipping charges are three 
times continental U.S. rates. If you have a 
Discover, Visa^ American Express or Master 
Card, you may call and place acredit card order. 
6% surcharge for biliing to American Express. 
Order toll-free in the U.S. Dial 800^ USA-SCAN. 
In Canada, dial 800-221-3475, FAX anytime, 
dial 313-971-6000. If you are outside the U.S. 
or in Michigan dial 31 3-973-8888. Ordertoday. 

Scanner Distribution Center" and CEI iogos are trade- 
marks of Communications Electronics inc. 

Sale dates 3/8/89 — 9/30/ 89 AD #030889'! 

Copyright © 1 989 Communications Etectronkca Inc, 

For credit card orders call 

1-800- USA-SCAN 

TW 

COMMUNICATIONS 
ELECTRONICS INC. 
Consumer Products Division 

P.O. Box 1045 G Ann Arbor. Miuhigan 48106-1045 U.S.A. 
For orders cal I 31 3-973-8886 or FAX 31 3-97 1 -6O0O 

CIRCJ.E 121 ON READER SERVICE CARD 




Number 1 2 00 your Feedback card 



Control Your Rig 

from a PC 

Simple interface for an IBM-PC or clone and 

many new synthesized HF rigs. 

by William Waters N7IPY 



Today's new, ftill-fenctioned i^otid-statc 
radios have many powerful features 
thai, with a little time and creativiry'. you can 
control frorn your computer keyboard. Many 
radios have a serial daia computer interface, 
composed of hardware and software* that al- 
lows you to change functions, such as the 
VFOs, RTT, and memory channels from your 
keyboard. 

Why would you want to do this? To save 
time and effort while setting and changing 
memory channel information. The Kenwood 
TS-440S, for example, has 100 memory 
channels, each holding the frequency and 
mtxle of operation. Adding or changing chan- 
nel data is ume-consuming; this program and 
interface makes it much less so. 

The Hardware Interface 

I discuss Kenwood radios here, but ICOM 

and Yaesu radios have similar interfacing 
capabilities. 

On the back of the Kenwood TS-440S. 
R-50()0, and TS-940S (added to the TS-7 11 S/ 
8115 with the Kenwood interface kit), there 



CONNECTOR 



2» 



TsD 




3^ 



RiO 



S* 



tTTS 



s*. 






is a connector labeled ACCi , This is the serial 
I/O port of the radio. The signal level is 5 volt 
TTL (Trans tstor-T ran sisior Logic)- This sig- 
nal level is not acceptable for most comput- 
ers, which require RS-232 voltage levels; 
i,e,, +12, —12. Directly connecting the ra- 
dio to the computer could damage the radioes 
control electronics. The first part of the hard- 
ware interface is the TTL to RS-232 level 
translator, with the proper interface cables 
and power supply voltages. See Figure L 

The basic translator or interface consists of 
three ICs, One IC is a 1488 quad line driver 
thaiconvens the TTL signal levels to RS-232 
signal levels. The second IC. a 1489, con- 
verts the logic level in the oppc^site direction 
{from RS-232 to TTL). The third IC, a 
74LS04 hex-inverter, inverts the radio's 
RXD and TXD signals. The interface elec- 
tronics require three separate voltages: +5* 
-h 12» and -12, all at a very low current. 

Kenwood radios have five interface signals 
on the 6-pin DIN connector, ACCl. for serial 
data communications. Figure 2 shows the 
signals and their pin numbers. Only TXD 

(transmit data), 
RXD (receive data), 
and GND (ground) 
signals are needed to 
communicate to the 
computer, but Ji is a 
good idea to include 
the CTS and RTS 

«t^woo^ *cc, "'^^^ *" ^ interface 

e Pin Bm design. 

For the computer, 
T used an IBM clone 



niD 



-*3 



Nflg 



■4* 



CTS 



?• 



SfiHO 






Uqt] 



io| \^a 



H«4 



RTS 



-*5 



r 



TO CQWPUTCn 



»4V H?V •tE.y 

I 1 I 

FI«JM POWER SUf*PLT 



with a multi-function board that supports 
two RS-232 serial data pi>rts. Both porLs 
are brought out to the back of the com- 
puter via two standard DB-25 connec- 
tors called COMl and COM2. By con- 
necting (through the interface) the radio's 
TXD to the computer's RXD, and the 
computer's TXD to the radioes RXD^ you 
achieve full communications between the 
radio and the computer. 

A Few Chips for the Rig 

For the Kenwood radios that support the 
serial interface, you need an accessory to 
enable this function. In the TS-*40S and R- 
5000, you must install two ICs into the con- 
trol unit: an 825 1 A (a UART, or Universal 
Asynchronous Receiver Transmitter), to 
con%^crt serial data to parallel data and vice 
versa; and a CMOS CD4040 1 2-stage binary 
counter to support the UART, Refer to the 
Kenwmxl instruction manual for details on 
the installation of these two ICs. 

This Kenwood accessory is called the "IC- 
10 Kit^^ for the TS^HOS and R-SOOO. It 
contains the two ICs and the instruction 
manual with all the information on the 
commands. If you plan to buy a ready-made 
program, you do not need the IC-10 Kit* You 
won't need the kit's software manual, and 
you can buy the two ICs from many electron- 
ics parts mail order companies, for a fraction 
of the COS! of ihe Kenwood kit. On the TS- 
940S/7 1 1 S/8 1 1 S, the interface kit consists of 
an additional circuit board, a new EPROM 
(Erasable Programmable Read-Only Memo- 
ry), and instruction manual. You will find 



F/^wre L The compmer RS-232 to Kenwood 5-voli TTL imerface 
schematic. 

34 73 Amateur Radio • August, 1989 



PIN 3 RxO IN 



W\H 2 TxD OUT 



9\H \ GROUMD 




PIN 4 GTS IN 



PIN 5 RTS OUT 



PIN 6 NO CONNECTION 



Figure 2. acc! DIN connector on the Kenwood rig. 



iif Lqutpnteni 

IC-76S Xcvr/ps/ke^fif/iyio tuner . 

IC-781 XcvtJ Rcvr/ps/tiiner/5cope 



Regular SALE 
.3149 00 2789 
.6149.00 Call 




IC-76I Xtvr/ Rcvr/p5/tunef ..2699.00 2365 

HM'JG Scanning hand microphone 47.00 

SP-20 Ed speaker w/audio filter .. 149,00 139*^ 

FUOl 250 Hz 1st IF CW filter..,.. 73.50 

Fi-S3A 250 Hz 2nd IF CW filter .... 115.00 109" 

FH02 6 kHz AM filter 59.00 

EX-310 Voice synthesizer... 59.00 




IC-751A 9'bancl xc\^r/.l'30 MHz rcvr 

PS-35 Internal power supply 

FL-63A 250 Hz CW filter (ht If).. 
FL-52A 500 Hz CW filter (2nd IF) . 
Fi'53A 250 Hz CW filter (2nd IF). 

FL-33 AM lk!fer„... 

FL-70 2.8 kHz ^fdeSSB filter.... 
RC-10 External Irequency conlmller 



1699.00 U69 
219.00 199** 

59.00 

115,00109'= 
1 15.00 109'^ 

49.00 

59.00 

49.00 




IC-735 HF transcetver/SW rcvf/mm 
PS'55 External power supply. .,,,.- 
AMM Automatic antenna tuner .„ 

FU32A 500 Hz CW filter ..* „ 

EX-243 ElectronEc keyer unit 

UT-30 Tone encoder ,^>^*.*,* 

IC-725 Ultra compact HF xcvr/SW rcvr 

Other Accessoriei 

IC-2KL 160 15m soiid state amp w/ps 

EX-&27 HF aotomattc antenna selector 

PS'15 20A external power supply 

PS- 30 Systems p/s w/cord. 6-pm plug 
MB Mobile mount 735/751A/761A... 

SP-3 External spealter .,„.;,,„. 

SP-7 Small external speaker ,,....,.„ 
CR-64 High stab. ref. xtal for 75 LA.... 

PP-i Speaker/patch w 

SM-6 Desk mtcfophone ,,.,. ,., 

SM-B Def;k mic - two cables. Scan..... 
SM-10 Compreisor/graph EQ, 8 pin mic 
AT- 100 lOOW 8 band auto ant tuner... 
AT<500 500W 9 band auto anl tuner... 
AH-2 8 band tuner w/nrouot & wtiip. .. . 

AH'2A Antenna toner system, only 

GC'5 WoeWdodi...... 



1149 00 989*^ 
219.00 199*' 
445 m 369*^ 

69,00 

64,50 

18.50 
949,00 849" 



Regular 

1999 00 

315,00 

1 75.00 

349,00 

25.99 

65.00 

5L99 

79,00 

179.00 

47,95 

89.00 

149.00 

445.00 

589.00 

758.00 

559.00 

9195 



SALE 

1699 
27955 

159" 
319'^ 



164« 



139" 
389'^ 
519^- 
689*' 
499« 
79» 



o 



I COM 



* Large Stocks 

* Fast Service 

* Top Trades 

at 




VHf/UHf hasp^ mutthmode^ 
IC-275A 25W 2m FM/SSB/CW w/ps 

tC-275H 100W2mFM/SSB/CW 

IC-375A 25W 220 FM/SS8/CW (ChsiA 
IC 475A 25W 440 FM/SS8/CW w/ps 
IC-475H 75W440FM/SSB/CW.,..,.. 

IC-575A 25W6/10m xcvr w/ps 

tC-575H 100W6/10mxcvr,„. 

VHF/UHf/lJ €Hz Mobiles 
IC-47A 25w 440 FM/TTP mic fChsmf) 

PS-45 Compact 8A power supply... 

UT-16/EX'3S8 Voice synthesizer ... 

SP40 Slim- line external speaker ... 

IC'2SA 25W 2m FM. TTP mic ffpBmO 
IC-28H 4&W2mFMnp mic. .,..„.. 

IC-38A 25W220FM,TTPmf£.. 

IC 48A 25W440 450 FM, HP mic.„. 

Nil- 14 Eitra TTP mitroplione ...,,. 

UT-28 Dig>tal code S(|uelctt....v.,*. 

UT'29 Tone SQuefch decoder....... 

HIUI ■ 1 6 Speaker/microphone 

IC^228A 25W 2m FM/TTP mic (Spiekl) 
IC-228H 45W 2m FM/TTP scan mjc... 

IC-448A 25 W 440 FM/TTP mic 

UT-40 Pocliel beep function 

JC'900A Transceivef contralfer........ 



Regular 
1299,00 
1399-00 
139900 
1399.00 
1599.00 
1399 00 
1699.00 



SALE 
1099 
1199 
799" 
1199 
1369 
1129 
1499 



Regular SALE 
549.00 369'^ 
145.00 1345* 

34.99 

3599 

469,00 379" 
499.00 439" 
489.00 349« 
509 00 449« 

59,00 

39,50 

46 00 

34.00 

509 00 429^5 
539.00 479" 
509 00 449" 
45.00 

639 00 569" 



r 



IC'900A Transceiver controJlef with UX'29H 
2II1/45W and UX-39A 220/25W t>and units. 

$969^ 



UX-19A 10m low band unit ...... 

UX-29A 2m25Wb3ndunit,..„,.,, 

UX-29H 2m 45W band unit 

UX-39A 220MHz 25W band unit.... 
UX.49A 440MHz 25W band unit. . . . 

UX-59A 6m lOW unit 

UX429A l,2GHz!DW band unit... 

IC4200A low 1.2GHz FM mobile. 

IC-250OA 440/1200MH2 FM mobile 

IC-3210A 25w 2m/440 FM/nP 

AH^32 2m/440 Dual Band antenna .,. 

AHB-32 Trunkiip mount .*. 

Larsen PO-K Roof mount „ 

Larsen PO-TLM Trunklip mount.... 

Larsen PO-Mli Magnetic mount.... 
RP-1210 l,2GHz low 99 cti FM xcvr 

RP^2210 220MHz 25W repeater ,„... 



299,00 
299 00 
349.00 
349.00 
349^00 
349.00 
54900 



2S9" 
20995 

319" 
259^5 

319^- 
319^^ 
499" 



699,00 599^* 

999.00 899" 

739.00 649" 

39.00 
35.00 
20.00 
22.00 
22,00 
1529,00 1349 

1649 00 1399 



Dui to the size of the I COM product line, some accessory 
ft«m$ are not listed. H yoy have a question, plaase caEI. 
All prices shown are subject to change without notice. 



Top Trades ! • We'll take your 
Clean Late Model gear in trade 
towards New ICOM Equipment, 

Write Of Call for our Quote Today! 




VISA 




Hand-hetd^ 

IC-2A 2-meters 

IC-2AT with TTP 

IC-02AT/Hi|h Power 

IC^04AT for 440 MHz 

IC-y2AT for 2m w/TTP 
IC-II4AT 440 MHz. TTP 



Regular SALE 
289,00 259" 
319.00 279" 

409 00 349" 
449.00 389" 

329.00 279" 
^9.00 289" 



FREE Battery! . . . 

BP 23 6CK)fna/8 4V • Pfo Cttaige with 
purt^ise of tC'UZAT or tC u4AT 



IC 2GAT for 2m, TTP 429.00 379" 
IC-4GAI 440MHz. TTP 44900 399" 

IC-32AT 2m/440MHz 629.00 559" 

Air (raft band hamihetds Refiuiaf SALE 

IC-12AT IW 1.2GHz FM HT/hatt/cgr/TTP 473.00 369" 
IC^12GAT IW 12GHz HT/batt/cgr/nP 529.00 469" 
A-2 5W PEP Synth aifcraft HT.......... 525 00 479" 

A-20 Synth airtraft HT w/VOR 625.00 569** 

Acceuories for aft encepi micros Regular 

BP'7 425mali/13 2V Nicad Pak - use BC-35 79.00 

BP-8 800mah/8.4V Nicad Pak - use BC-SS... 79 00 

BC 35 Drop in desk charger lor alJ batteries ?9-00 

BC-16U W3IJ charger for BP7/8P8,.. 21.25 

LC-ll Vifiyf case lor Oi)t using BP'3 .,. 20.50 

LC 14 Vinyl case lor Dh usmg BP-7/8 20.50 

LC OZAT Leather case lot DIx models w/BP-7/8 54 50 
Accessories for iC and tC-O series Regular 

BP-2 425mah/7.2VHicadPak useBC35.... 4900 

BP 3 Ixtr^ Std. 250 mati/a.4V Nicad Pak ,... 39 50 

BP-4 Afkaline battery case 16 00 

BP-5 425mah/l0 8V Nicad Hk - US€ BC35 6500 

CA-5 5/8 wave telescopmg 2m antenna . 19 95 

CPa Cig liEhtef ptug/eord lor BP3 or Dli..., 13 65 

CP-IO Battery separation cable w/clip «..,*.* 22,50 

DC-L DC operation pak for standard models 24,50 

MB-teO Mobite mtg. bkt for all HTs...m 25.99 

LC-2AT Leather case for standard models..... 54,50 

RB-l Vinyl waterproof radio bae -■— 35 95 

HW-9 Speaker microphone .^ 47 00 

HS'lO Boom microphone /head set ,,...,., 24,50 

HS'lOSA Vox ur^it lor HS-10 & Deluxe only 24.50 

HS-IOSB Pn urnt tor HS-10...... 24 50 

SS-32Sli(IP C&mmspet 32-lone encoder 27 95 

For other HI Accessories not listed please CALL 



R-7IA lOOkHz to 30fVtHz receiver. 

RCll infrared remote controller.... 

FL 32A 500 Hz CW tjlter 

FL^63A 2 50 Hz CW filter (1st IF).... 
FL 4flA SSe filter (2nd IF)„.„„,„„ 

EX 3iO Voice synlhesirer 

CR-64 High stability oscillator xtal 

SP-3 EjcternaJ speaNer ...,. 

CK-70 (EX-2901 12V DC option...... 

HB-12 Motitle mount,,....... 

R-7000 25MHz to 2GH7 scan rcvr 

RC-12 Infrared remote controller.... 

EX 310 Voice synthesizer 

TV'R7000 ATV unit... »,*,„,*,.,* — 

AH -7000 Riidiating antenna ../.,,.,. 
R'90O0 100KH2-2GH^ ail mode rcvr... 



Regular 

$999.00 
70.99 
69.00 
5900 
178.00 
49.00 
59.00 
79.00 
€5.00 
12-99 
25.99 

1 199.00 

70.99 

59.00 

139.00 

9900 

5459.00 



SALE 



159 



*5 



1029 

129'^ 
4899 



HOURS • Mon. thru Fri. 9-5:30; Sat. 9-3 

WATS lines are for Quotes & Ordering only, 
use Regular line lor other Info & Service de pi 



Order Toll Free: 1-800-558-0411 



I 



In Wisconsin (outside Milwaukee Metro Area) 

1-800-242-5195 



T 



I 



Inc, 



4828 W. Fond du Lac Avenue; Milwaukee. Wl 53216 

AES® BRANCH STORES 



Phone (414) 442-4200 

Associate Store 



WICKLIFFE. Qhia 44092 
2B940 Euclid Avenue 
Phone (216) 585^7388 

Of^io WATS i-800-362 0290 

^Sh'f 1-800*321-3594 



ORLANDO. Fla, 32803 

621 Commonwealth Ave. 

Phone (407) 894-3238 

Fla. WATS 1-800-432-9424 

Outside 1 rtAA nrfi-T mn 



CLEAflWATER, Fla. 34625 LAS VEGAS. Nev. 89106 CHICABOJIIJiiois 60630 



1898 Drew Street 

Phone (813) 461-4267 

No In-State WATS 



1072 N. Rancho DrEve 
Phone (702) 647-3114 

No In-State WATS 

Outside 1 QAA C^M rii 



1-800-327-1917 No Nationwide WATS Kdn-800-634-6227 



{RICKSONCOMMUNiCATIONS 

5456 H. Milwaukee Avenue 

Phone (312) 631-5181 

?ift!,^^' 1-800-621-5802 



this kit at a Kenwood dealership. The inter- 
face kit for ihc TS 71 IS/SHS is called the 

'*IF-10A*^ and the interface kit for the TS- 
940S is called the * *IF- lOB/ ' Both come with 
instruction manuals^ 

The Software Interface 

After the h;jrdware is ready, the software 
must be developed. The Kenwood radios 
have an interface language consisting of 17 

commands for \hc R-5000. 19 commands for 
the TS^WOS, 20 for the TS-71 1 S/81 1 S, and 
22 commands for the TS-940S. These com- 
mands allow the control of functions like: 

— Programming and recall of VFO A and 
VFO B frequencies 

— Memor>^ Input and Memory Recall 

— Memory Channel Selection 

—Mode Selection 

— Control of RIT/XIT and frequencies 

—Complete status updates of the radio 
operations 



IfHtilize 

data arrays 
Draw Screen 



InmUzs COM 
Port to B&r. 
Ho Parity. 4800 
Baud. 2 Slop Stts 



I 



Qufpul AEI, 
Command 



I 



t'nptit Loop 
Pd+e COM P<irt 
lor Data. 



CteajrCaunlsf 
Display EnROR 
Message and Si art 
Over. 




Gm From U AH T 
anti Pui mm 
Input Array. 
incremenlcchjrH 




DiSiptay Oim. 
Clear courtttfrs 



T 



Figure S. Fhw chart for the radio status 

moniioring program, 

36 73 Amateur Radio • August, 1989 



Along wiih ihe basic commands, there is a 
wdl-defined protocol for conirolling com- 
munications between the two pieces of equip- 
ment. After every command from the com- 
puter or response from the radio, a semicolon 
'* ; " is sent at the end of the data or command 
packet to tell the other end that the transmis- 
sion is complete. The radio can tell the com- 
puter that it could not understand a command. 
If the computer sends data loo fast, the radio 
will reply with an *'E:'' which signals an 
overrun or framing error in the transmission* 
If the command syntax is incorrect, or the 
radio cannot execute a command, it replies 
with a **?;*' which informs the computer of a 
problem. 

I prefer the programming language **C," 
but you can use BASIC. FORTRAN, PAS- 
CAL, or another language. The most impor- 
tant considerations arc the language's speed 
and its ability to send and receive data from 
the communications port. Below is an exam- 
ple of how 1 communicate to the UART using 
*-C'*: 



ch _ in 
Where; 
ch_ in 

io _ adr 
inportbO 



= i0portb<io _ adr) ; 



= the data from the UART 

— the hardware port address. 

— the input function. 
oiitpQrtb(to _ adr.ch _ out); 
Where: 

ch_out = the data to be scut. 

10 _ adr = the hardware port address. 

outportbO ~ the output function. 

At first, I used the language's high level 
interface to handle the UART» but that was 
not fast enough, so I had to go to a direct I/O 
method. These commands would be very 
similar in most languages. The main thing is 
to get data to and from the UART as fast as 
possible. 

Three of the common commands the radios 
support are: 

ID; Identification of radio type. Reply as 
follows: 

IDO0i;-fortheTS-7US. 

10002; for the TS 8113. 

ID003;-fortheTS*940S. 

ID0O4;-forthcTS^440S, 

ID005;-forthcR5000. 

AIx; Turn ON or OFF the Automatic In- 
formation transfer from the radio. Here» 
X = I for ON and x = for OFF. The reply 
data format is the same as the IF; command. 

IF: This command asks for the radio's cur- 
rent condition. The reply data packet is 38 
bytes long, and structured as follows: 

Bytes Description 

1 and 2 IF. Command name. 

3 to 13 Selected VFO frequency in Hz. 



5 BZX lOTEST^BAS - ihterfdcv test Prograp 
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80 PRIMT h$: 
85 COTD 30 
90 ENtJ 



Figure 4. BASIC program for testing the com- 

puier/rig interface. 



19 to 23 

24 

23 

26 

27 to 28 

29 

30 



31 

32 
33 
34 

35 to 36 

37 

38 



Note that the first three b}ies are not used. 
1 4 to 1 8 Step frequency in Hz for 

TS-940S* TS-71 1/811. 

RJT frequency, 

(E,g. +OiOOor-1250.) 

RIT On/Off. l=On, 

and 0= Off. 

X IT On/Off. l^On. 

and 0= Off 

Memor>' Bank. TS-940Sonty. 

Memory channel. 

TX/RX„0=RX,andl-TX. 

Mode. 1=LSB,2=USB, 

3=CW.4 = FM,5=AM. 

and6=FSK. 

AM, FSK. TS-440S/R500W 

TS'940Sonly. 

Function. 0-VFO A, 

1=VF0B, 2= MEMORY. 

Scan On or Off. 

Split On or Off. 

Tone On or Off. TS-81 1 A, B, 

E/711A, Eonly. 

Tone Frequency, TS-81 1 A, 

6/711 E only. 

Offset, = Simplex , 

1 = + ^2^ -,TS-7I 1/811 only. 

Terminator character. 

This is":". 
The IF: command need not be sent for con- 
stant updating of the data array, because the 
radio wilt automatically s^nd the data packet 
every time one of its settings or conditions 
change, provided the ah-. (AI on) command 
has been sent. 

Testing The Hardware 

After the hardware is assemble, connect 
the IBM PC or clone to the radio via the 

interface unit. A test program, lOTEST. 
HAS, is given in Listing L It is written in 
GWBASIC, but other versions of BASIC will 
work with little or no changes to the code. 

The program initializes the computer's 
COM2 port, sends a request to the radio for 
information, and then waits for data from the 
keyboard or serial port. If data from the radio 
is sent, the computer will display it on the 
screen. If you press a key, it will display that 
character and then send it to the radio. If your 
serial port is COM I. change line 15 accord- 
ingly. This simple test program does not do 
any error checking and is intended only to test 
the hardware function. 

Enter the program and nm it. If you rotate 
the VFO knob, you should sec a block of 38 
bytes displayed on the screen. If so, your 
interface electronics arc working properly. If 
not, go back and check your work. You will 
notice that the radio sends the data only w^hcn 
a condition has changed in its operations or 
settings, and then only after one to two sec- 
onds after the change occurred. This is a 
feature of the radio's control microprocessor. 
It doesn't send serial data when it is busy 
doing other operations, such as dealing with 
the VFO tuning knob as it is rotated. This 
ensures that all changes are completed before 
the FMlio sends out new data. 

A Simple Program Example 
Because a full-functioned control program 



is loo complex for an article, I give here only 
a simple and understandable example. The 
flow chart shown in Figure 3 will help ihose 
programming in differeni high levei lan- 
guages. 

Initialijcation 

This is where the program stans. Dcfme 
any variables, if the language [leeds them. I 
recommend using a 38 byie array for storing 
the radio information as it is received. Initial- 
ize the serial data pon for 4800 baud, eight 
data bits, two stop bn^, and no parily. You 
can also paint the display screen at this point. 

Input Loop 

The input loop should be as fast as possible 
with minimum steps, thereby allowing 
polimg of the input port. If done correctly « 
you will be able to run the program on the 
slower4,77 MHi IBM PC. When a character 
is ready, read it into the input array and incre- 
ment the array pointer, making the DART 
ready for the next character* 

After reading a character from the UART» 
three conditions must be tested: 1 ) whether or 
not the input array is full, indicating a com- 
munications problem; 2) whether or not the 
last ^ecei^'ed character was a *'?" or an * 'E/ ' 
indicating a communications problem; and 3) 
whether or not the character was a **;" indi- 
cating the end of the data packet from the 
radio. If the data was received and terminated 
properly, you will want to display it on the 
screen, overwriting the old screen data. If 
any of the error conditions exist, you will 
want to display a small error message, reset 
the array pointer to 0, and get ready for the 
next packet of information. 

Where To Get Parts 

All of the parts tn the basic interface unit 
are available at Radio Shack. The Radio 
Shack part numbers are listed below. The 
interface kits IF- 10, IF-IOA. and IF- 1 OB are 
available from any Kenwood dealer. You can 
also get a full-featured program for the Ken- 
wood from Rad-Com. PO Box 1166, 
Pleasanton CA 94566; 408^*43^633. 

Concttiston 

From this basic understanding, you could 
design a very comprehensive program to con- 
trol the functions of the radio in a real-time 
operating mode. Along with the novel pro- 
cess of controlling the radio from the comput- 
er, you accomplish a much more important 
function— full memory^ channel management 
through your computer, which saves you 
time and makes the radio easier to use. 



i Parts List for Simph 


s interface Unit 


1 MC14S8 Line Driver 


RS# 276-2520 


I MC1 489 Line 




Recerver 


RS# 276-2521 


1 7404 Hex tnvefter 


RS# 276-1 802 


3 14 Pin Sockets 


RS# 276- 1999 


1 6 pin DIN Plug 


RS# 274-020 


1 Small PC Board 


RS# 276-158 


Misc.: Small enclosure, 


cable, low current 


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73 Amateur Radio • AtjgusM989 37 



Kumber t^ on your Feedback canct 



73 Review 



by Jim Kocsis WA9PYH 



Ramsey 

SR-1 Receiver 

A lot of listening fun at an 
affordable price. 



Ramsey Electronics 

2575BairdRd. 

Penfield NY 14256 

(716)586-3950 

Price Class: $25 



Photo A. Top view of the the Bssemtled Ramsey 
SR-1 receiver. (Photo courtesy of Bob W8MDV.) 




Ramsey Electronics off&rs inexpensive 
kits ranging from frequency counters to 
LED blinkers and small receivers. This simple, 
inexpensive AM-only shortwave receiver is a 
great starter project for budding hams. 

Assembly 

The parts come \n a plastic bag with a sin* 
gEe-sided phenolic PC board that has a solder 
mask but no component markings. The ab- 
sence of a component layout on the board 
isn't a problem because the page that accom- 
panies the kit shows the location of all the 
parts. I strongly recommend placing all large 
components first (transformers, pots, antenna 
connector, etc.). Next, mount all the resistors 
and capacitors. Add the transistors, diodes, 
and ICs last. Don't "jump the gun" ItKe me 
and forget the jumpers. (I was anxious to see 
how this little receiver worked.) 

This unit is easy to assemble. For an ex- 
pedenced Mt buifder, the assembly time is 1 to 
2 hours. All but one part fit perfectly; there 
was not enough room for the large 220 pF 
capacitor at pin 8 of the NE602 IC, i managed 
to make ft fit on top, but you could also mount 
it beneath the board. The disc capacitors are 
not all marked as described, but by the pro* 
cess of elimination you can figure out that 
the 100 pF capacitors are marked 100k, not 
101, and the 0.01 pF capacitors are marked 
0.01, not 103. I would guess that Ramsey 
switched sources for their parts so the instruc- 
tiofis are not quite correct. The mismarkad 
components are reafly a very small point, 
since overall the assembly was very easy and 
straightforward. 

Two of the transformers need to be modified 
by breaking out a small internal capacitor. 
Otherwise, all parts can be used as supplied. 
There were no extra holes in the board and no 
extra components. (The appearance of myste- 
rious extra holes or parts can be confusir>g to 
the beginner. Ramsey did really well in this 
area,) 

Tuneup and Operation 

1 applied power (a 9 volt battery), added a 10 
foot piece of wire for an antenna and an ear- 

38 7$ Amateur Radio • August. 1969 



phone, and immediately began tuning in 
LOTS of shortwave stations. Actual tuneup 
consists of peaking a single 262 kHz IF trans- 
former and presetting the local oscillator and 
antenna coils for the desired 2.5 MHz seg- 
ment of the receiver's 4-10.5 MHz coverage. 
In a few minutes of listening I heard the BBC, 
CBC, and many Spanish-, German-, and 
French-speaking stations. 

The three controls— RF gain, AF gain, and 
tune— are potentiometers. Use the RF gain if 
there's so much signal coming in that the sim- 
ple AGC circuit can't handle it. The audio out- 
put is more than enough for an earplug, but 
there isn't sufflctent audio for even a small 
speaker. 



'\ . . assembly time 

(for the SR'l) is 1 to 

2 hours. " 



Technical Informatfon 

This receiver uses the Signetlcs NE602 for 
the mixer/local oscillator; a two-transistor IF 
amplifier with a doubly-tuned transformer 
comes next. The IF amps are followed by 2 op 
amps used as an audio preamp, and an AGC 
amptifier. A singie transistor forms the audio 
output stage. Current draw at 9 volts is 45 mA, 
so the battery should provide many hours of 
listening. 

Plusses: The receiver is really hot, mostly 
due to the NE602. The chip is just coasting in 
this frequency range— it can actually operate 
up to 500 MHz RF input with its own local 
oscillator running at 200 MHz. The assembly, 
tune-up, and operation are all very straight- 
forward. No special tools or equipment are 
required. 

Minuses: The overnding problem with the 
receiver is: ''What is the frequency?" There is 
no frequency indication—all tuning is done 
with a pot-tuned varicap (voltage variable ca- 



pacitor) and the oscillator coil. There are also 
a few heterodynes as the receiver is tuned 
throughout the selected range. This is an indi- 
cation of inadequate front-end selectivity. An- 
other problem area involves the Hf and oscil- 
lator coils. Tuning these eoits requires a very 
small screwdriver-type alignment tool I've 
seen these types crack after several adjust- 
ments. Adjust them sparingly or consider ir>- 
stalling another type of coil. 

Modifications 

As an option, you can supply an external 
oscillator signal to the NE602. It should be at 
least 200 mV peak-to-peak. Ramsey doesn't 
provide this option or descht>e it Consult the 
Signetics Linear Data Manual, Volume 1 for 
more information on this IC, 

For the experienced builder, 1 would recom- 
mend adding a BFO or product detector for 
CW/SSB reception, an LM3S6 audio stage for 
speaker operation, and more tuned RF stages 
to improve the image rejection. Some type of 
frequency synthesizer in place of the local 
oscillator would also be useful. (Signetics and 
other companies make several synthesizer 
chips that might be used here.) 

Another option for frequency read-out is the 
addition of a simple buffer and frequency 
counter This could involve a lot of work and 
extra parts, and would detract from the sm- 
plicity of this receiver. 

An Overall Good Deal 

Am [ glad I bought thfs receiver? You bett 
I plan on putting it in my car and listening to 
SW instead of the local AM-FM broadcast 
"chatter/' or when 2 meter FM is inactive. 
Ramsey did a fine job on this receiver. The 
price is reasonable, and all parts are high 
quality. (Ramsey uses the same NE602 chip 
in their 30/40 meter hamband receiver^ in 
a 2 meter receiver and in an aircraft receiver — 
all reasonably priced.) You can also buy an 
optional plastic receiver case for Si 2.95. 

Do you remember your first kit or project? 
IVe been building kits and home-brewing 
since 1962, I can honestly say that this 
one was nearly as much fun as the first J 



. T ii 



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^# I ^#^^^J^^# Contiruied front fHiiie 16 

ter, will generally be sausfacior>'. In one or 
two cases, with older synthesized transceiv- 
ers usirtg the Motorola MC4044 Phase/Fre- 
quency Detector in a phase-locked Icxip cir- 
cuit, we obiained ihc best resulLs w^hen we 
coupled the output of the PL board directly to 
the varactor diode. If you do this, make sure 
that the 0,47 (or 0.50) pF capacitor is nm a 
tantalyiic. 

Just as some manufacturers provide a con- 
necting point for a PL i^igniil, some also offer 
a from panel switch-controlled power source. 
Such was the C3se with the Kenwoixl and the 
Azden models. If so. by all means take advan- 
tage of it* Even though this CTCSS board 
uses very little current. it*s preferable to take 
it from the transmitter source. 

The circuit diagram of Figure I suggesits a 
Vcc of !3.8 volts, but any voltage from 6 lo 
13.8 works, as long as that is the voltage 
applied when tuning the oscillator. The cur* 
rent requirement varies from about a low of 
7,4 mA at 8 volts to about 9.5 mA at 1 2 volts* 
1 1 should not pose a problem for even a small 
battery. 

If you use a mechanical relay to switch 
power to the transmitter finals . you can usual- 
ly find a switched positive 8- 12 volt source at 
one oF the relay terminals. To get the tone 
when you want it, put a wire from that point 
to a mechanical switch at some accessible 
place on the cabinet* and from there to the 
CTCSS supply lerminaL The switch lets you 
disable the tone when you don't want it* 

When you use a transistor switch, rather 



than a relay, to key on the transmitter finals. 
you have a couple of choices. If you're sure 
about what you're doing, pick up the B-12 
volts your rig uses at the same point that the 
transmitter final uses it. Bring the ground 
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the emitter, as the case may be) of the transis- 
tor that actually keys on the power transis- 
tors. If you're not comfonable doing that go 
lo the same source point, but take I he ground 
wire from the CTCSS board to the open side 
of the PTT (Push-to-Talk) switch in the micro- 
phone circuit. You will probably still want to 
use a mechanical switch to disable the CTC- 
SS board when you're not operating PL, 

If you Te not using a voltage source provid- 
ed by the manufacturer, ii*s a gotxl idea to 
protect the CTCSS circuit — and your audio 
signal — against unwanted RF. Use the 0.00 1 
\i¥ bypass cafiacitor as shown on the sche- 
matic. 

Various Installations I Have Done 

Photo B shows the underside of a Conarc 
452 2-meter transceiver The CTCSS board 

seen at ''A" was the prototype installation. 
You can get a feeling for the size from the 
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center, and the ^-4 -watt resistors. 

At the left of the chassis, just inside rH" the 
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nal that goes to 13,8 volts when the transmit- 
ter is keyed on, provides the voltage source. 
A toggle switch, barely visible near "P," 
iniemipts the current supply when you don^i 



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want PL operation. Because of the length of 
wire needed to get from the relay* [o the 
switch, to the lone board, an RF bypass ca- 
pacitor (see Figure I ) was used. The CTCSS 
tone is injected ai the varactor diode used for 
modulation. There are two small potentiome- 
Eers on ihc right end of the board: one for 
frequency controL and the other for signal 
amplitude. Unfonunatcly, the devices avail- 
able from Radio Shack are not as liny as the 
junk box specials seen here. 

In the Azden PCS 4000, the manufacturer 
provides both a connection point for the tone 
signal and a switched voHagc source for the 
board. The signal-in point is shown on the 
transceiver's schematic as the inverting input 
on an operational amplificrL the microphone 
input is the nonin verting input of the same 
device. 1 mounted the board at the front end 
of the component side of ihc Azden's main 
board, in the left comer* when facing the 
front panel. 

This installation furnished an interesting 
problem. The circuit diagram that came with 
the Azden is wrong. It shows a terminal, 
J406, and ideniines this pin as the tone input; 
supposedly the input to the op amp nofed 
above. Actually, it is the terminal which pro- 
vides 8 volts when the tone switch on the rig's 
front panel is engaged and the ptt squeezed. 
To get to the op amp (at '"B"), you must 
connect the wire from the CTCSS board to a 
lead of resistor R464. Otherwise there was no 
difficulty. Even the best of us make mistakes! 

Installing the board in the Kenwood TR- 
7S50 was straighiforuard. The manufacturer 
provided junction points (see the manual) for 
the tone signal, Vcc^ and signal ground. We 
butit the board to be as narrow as possible. 
and longer, so that it could be positioned on 
edge behind the front panel, 

Because of the high risk of shorting against 
other devices, a piece of cardboard, cut to Tit 
and taped to the bottom, exposes only the 
tuning potentiometers. Again, because the 
hook-up wires stretch quite a ways across the 
transceiver chassis, recourse was made to the 
bypass capacitor. It is mounted on the under- 
side of the CTTCSS board. 

Conclusion 

With these examples and yviur imagination, 
you should have very little trouble adapting 
the circuit to your rig. Although the design is 
for a single tone, you can readily mtxlif)' it to 
offer two I ones by adding anoiher tuning pa- 
lent iomcter, a fixed resistor, and if neces- 
sary, a switch, ff you have to use an external 
power switch, as we did lor the Conarc 452, 
you could make it a double-pole-doublc- 
ih row-center-off switch to do double duty for 
ON /OFF and frequency select* 

Think Ri^ 



40 73 Amateur Radio • August ^ 1989 



CIRCLE 1B3 ON READER SERVICE CARD 



easy, one- or two-^vcning pnqcct is 
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trustee* With any luck, you'll find one close 
at hand, and you'll have the pleasure of 
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J 




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Full- Wave VHF Vertical 

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Easy-to-build, good gain antenna. 

by Don Norman AF8B 



This full-wave vertical antenna grew out 
of a ^enm t^f experiments with the verti- 
cal J antennii. The result ts a full-wave anten- 
na easily built by the average amateur. The 
final version of the antenna \% matehed by a 
form of ganuna match, anil features full RF 
decoupling from the teed line. 

The anictina can be grounded and in fact 
may be a continyation of the supporting mast. 
The 52Q coaxial feed line runs up inside 
(MUST be inside) the antenna., It emerges 
through a % " diumeter hole next lo the feed- 
point on the matching stub. The diameter of 
the radiator docs not seem to be critieaL as 
working model j; have been buifi with radiator 
diameters ranging from %" to VA". 

Antenna ditrkensions for 145 MHz (packet) 
are given in Figure I . You can easily build the 
antenna from a 10~foot length of V^* electri* 
cal conduit. The insulators are fabricaicd by 
ctilting a plastic pipe tee in half. This plastic 
pipe tee. used mostly with scmi-fle.\ible plas- 
tic pipe joined with molded fittings and hose 



40-S' 



19 3/4' 




RAOtALS 19 4* LONG 



i 



Figure J. Full- wave veri teal dimensions for 
145 MHz. 

42 73 Amateur Radio * August, 1989 



clamps, is common in hardware stores. A 
.single ]*' tec cot along the line shown in 
Figure 2 will yield two insulators that will fit 
over the *^" EMT tubing. 

Cut the maiching rod from #tO copper 
wire, 3/32** brass brazing rod, or '^"copper 
tubing. Cut the radjals from brazing rod or 



hard aluminum wire, and attach them to the 
radiator with self-tapping sheet metal screws. 
The first step in building the antenna is 
dritiing holes in the metal tubing for the coax 
and radial attachment, Mark one end of the 
tubing **Top/' Drill a H" hole through one 
side of the tubing 40'/^ '* from liie top. Drill 




Figure 2. Make ihe insulators by iutting aptasHcpipe tee in half. 



h 



■mA 



K t'' ," .'^' ..' - ' ■ ■ 
b">'.".' ' ' ' » ' 1 

P„H_P_*,« ■ ■ » J ™ 

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ELEMENT 



■.'.'.'.■xV+V 

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-'^w 






^: 



RADIATOR 



Figure S. Matching element and btmotn insulator attachment to verticat element. 



three or four '/4 " holes for sheet metal screws 
59^ " from the top. Use a round file to re- 
move burrs and snags from the inside of ihe 
%* hole. Fish ihe coax cable up through the 
tubing past the small holes and out through 
the %" hole. Figure 3 shows the malching 
element and bonom insulator. 

Cut the insulators. Measure and cut the 
gamma matching rod. Slip the insulators over 
the tubing and measure 1" from the main 
tubing, then drill small holes through the pro- 
jecting part of the insulators large enough u> 
accept the matching rod- The distance be- 
tween the radiator and the matching rod is 
critical . Use your best concentration, and 
make the spacing as near to I " as possible. 
Refer to Figures 3 and 4 for proper bottom 
insulator placement. 



Install the radials. Cut the radiak 1 " longer 
than the correct dimension. Bend one end in a 
small circle and anach the radials to the radia- 
tor widi sheet metal screws. CAUTION! 
Don't pinch the coax with the screws! The 
radials are clipped to the correct dimension 
after they are installed. The radials, an essen- 
tial part of the antenna* decouple the RF from 
the support and feedline. Their dimensions 
are as critical as the nsst of the antenna. 

Performance 

Checking the antenna with an absorption 
wavemeter indicates the presence of RF from 
the tips of the radials upward in the classic 
patterns depicted in the various antenna 
manuals. 

On-the-air tests indicate it is equal lo or 
bcner than a commercial ^-wave vertical. 



Choose Your Resonant Frequency 

Dimensions for frequencies other than 145 
MHz may be calculated as follows: Radiator 
above the feedpoint, 5872/Freciuency 
(MHz). Ftxdpoini to radial attachment point, 
2790/Frequency (MHz). Matching rod 
length, 2865/Frequency (MHzK Radial 
length, 2810/Frequency (MHz). Matching 
rod spacing, 146/Frequency (MHz). The 
spacing of the matching from the radiator is 
the nioKt critical measurement, A quarter- 
inch more or less makes a greai difference in 
the performance of the antenna. Radial length 
and placement are somewhat critical and 
should be within a half inch of calculated 
dimensions, 

Thai's all there is to it. Enjoy solid signals 
with this easy-build vertical! 



". - - the antenna 

is matched by a 

form of gamma match, 

and features fuH RF 

decoupling from 

the feediine. " 



Slip the bottom insulator over the radiator, 
place it as shown in Figure 4. and drill a small 
hole through the insulator and the radiator. 
LcKk the insulator in place w ith a self-tapping 
sheet metal screw. Attach the shield of the 
coax under this screw. Cut a 3 " piece of small 
bare wire. Wrap one end around the gamma 
rod an inch from the end and solder. Slip the 
second insulator over the radiator. Slip the 
matching rod through the holes in the insula- 
tors. Solder the center conductor of the coax 
to the end of the matching rod. Move the top 
insulator upward agains! the 3" wire soldered 
to the matching rod . Bend the wire around the 
insulator and wrap around the matching rod. 
Lock the insulator in place w ith a sheet metal 
screw. 

Figure 4 shows the bottom insulator rotated 
90 degrees from Figure 3. Notice that ihc 
coax end is protected by the semi-circular 
bottom of the insulator. 




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Figure 4. Bouom insulator placement. Tlie 
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73 Amateur Radio • August, 1989 43 



Number t6 oa your Feedback card 



Find Your Signal the First Time! 



Getting the shift of it 

by David G. Hart AA6CQ/VE6 



So where is your sigfial on the bird? 
You've got your new Mode B cquipmeni 
and you continue having trouble locating 
your downlink frequency. The most Likely 

problem is the Doppkr shift. Once you have 
Ihe translation frequency figured out, you 
still have to account for the dreaded Doppler 
shift. This shift not only makes it difficult to 
locate your own signal and scan a QSO. but 
you may also inadvertently transmit right 
over someone else. This is especially critical 
when the bird is crowded. 

In this anicle I will explain a little about the 
Doppler shift equation (unfonunaiely, yes), 
the Doppler shift effects, and illustrate some 
simple methods to find your signal the first 
time, and 1 will let you in on some simple 
rules. Included is a simple BASIC computer 
program to help you along. 

The Doppler Shift 

Everyone has experienced the Doppler 
shift, first described by Christian J. Doppler 
in 1330. When a speeding train is approach- 
ing you and blowing its whistle, the whisde^s 
pitch becomes higher and higher until it pass* 
es you, then it becomes lower and lower in 
pitch as the train recedes from you . The same 
thing happens to your radio transmission to 
the satellite- Camplicating this is that you are 
both transmitting TO the satellite and receiv- 
ing FROM the satellite at the same time. You 
have to account for Doppler shift on both the 
uplink and downlink channels. 

The Doppler shift equation is: 

r* = (o± Vr/c(fo) 

where jljj is the tt^nsmitter frequency mea- 
sured at the transmitter and/* is the received 
frequency. The ± means that the received 
signal can be either higher or lower than the 
transmitted frequency , depending on whether 
the satellite is moving towards you or away 
from you. Vr is the relative velocity of the 
satellite, and r is the speed of light. 

If the satellite is moving towards you. the 
signal received will be higher than the actual 
signal the satellite is transmitting. Vr is posi- 
tive. Also, the frequency the satellite receives 
wit] be higher than your actual transmitted 
signal. The difference in frequency is due 
solely to the magnitude of the relative veloci- 
ty, Vr, 

Typical maximum relative velocities are 
around 4 km/s (14,400 km/hi). Fortunately, 
these occur generally at or near perigee, 
where you won't be operating much. 

In general « the magnitude of the relative 
velocity is the key to knowing the proper 

44 73 Amateur Radio • August, 1989 



uplink frequency. Here I will calculate the Vr 
from actual satelliie transmissions. You c^n 
calculate Kr directly from orbital data or slant 
range (the distance from you to the satellite), 
but it is tedious by hand. Many programs arc 
available to do die calculations. ORBIT-II 
is an MS-DOS program available from 
AMSAT which also calculates Doppler shift. 

Calcutating the Shift 

All major satellites have beacons. Since 
these beacons are on a fixed known ftnequen- 
cy , it is very easy to use the Doppler equation 
to calciilate the relative velocity, and then go 
on to calculate other Doppler shifts. 

For example, the beacon frequencies on 
OSCAR 13 are 145.985 and 145.812 MHz on 



Mode B: 436.677 and 436.651 MHz on 
Mode JL; and 2400,664 MHz on Mode S. 
Simply listen for any of the beacons and note 
the frequency that you hear them on. They 
will be different from the actual transmitted 
frequency. If you hear the Mode B engineer- 
ing beacon at 145.813500, the Doppler shift 
is 1500 Hz. To calculate the relative velocity, 
insert these numbers into the Doppler shift 
equation and solve for Vr: 

145,813,500 = 145,812,000 + 
Vr (145,812,000/300,000) 

Vr is equal to 3.09 km/s 

Note that the apparent shift of 1500 Hz 
does not mean that your uplink frequency is 



145*812 
581 *39 8 
435.651 
1705*356 
2400-664 
1965*1 T 
■Copy rig 



1 ModeBB* = 

20 ModeBT* = 

30 Mode LB # = 

40 HodeLT* = 

50 HodeSB# = 

60 ModeST* = 

70 CLS:Frlnt 

80 Print "OSCAR-13 Do 

90 Print "Select Mode 

1 DO Hode$ s Input$( 1 } 

110 Print « Enter Rece 

120 Input flXBFi^ 

130 Print ^'Enter Rece 

140 Print "To exit en 

150 Input RxSFi 

160 If BxSWi < 14.0 t 

1T0 IF Mode* = "S" or 

180 IF Hode$ = ""L" or 

190 RVI = {(RXBF#-Mod 

200 SatTxF# = CRxSFi/ 

210 SatRxFf = ModeBTf 

220 GOTO 300 

230 ev# = CCRXBF-Hode 

240 SatTxF# = ( RxSF/ ( 

250 SatRxF# = SatTxF 

26 Goto 30 

270 RV# = ((RXSF-Hode 

280 SatTxF# = (RxSF/{ 

290 SatRxFi = HodeLT 

300 Dplink# = (SatRxF 

310 CLS 

320 Print "YOUH UPLIN 

330 Print Using "#### 

340 Print "Your Recei 

350 Print Using «###• 

360 Print "Relative v 

370 Print Using "-^#^fi^# 

380 Print " km/a" 

390 Print 

400 GOTO 1 30 

410 CLS:Print "Goodby 



ht 1999 by David G. Hart, AA6CQ/VE6 
ppler Shift Caloulator" 

(B,L,S) «; 
:Print Mode$ 
ived Beacon Frequency (MHz) 



It t. 



ived Station Frequency (MHa;) 
ter a number leas that 14** 

hen GOTO 410 
Model = "s" then goto 230 
Model = *1** then goto 270 

eBB#)/ModeaB#)» 300000.0 

(1+RV#/300000.0) ) 
- SatTxFI 

SB)/ModeSB)*300000 
1+RV/300000) ) 

- ModeST 

LB)/ModeLB}»300000 
1+RV/300000)) 

- SatTxF 
#/(1+RVI/300000.0) ) 

K FREQ = " J 
,####" ;Uplink# 
ve Freq = " ; 
####";RxSF# 
elocity s"; 
#.##" iRV#; 



e":END 



BASIC program for calcuhning Doppler shift for the six different modes. 



shifted by 1500 Hz. In fact, your Mode B 
uplink frequency will be shifted by 4500 Hz* 
For example, ifyoy hear a station on 145.905 
MHz, the satellile is actually transmitting 
1500 Hz LOWER at 145,9035 MHz. As OS- 
CAR- 1 3 Mode B \s an inverting repeater with 
a translation frequency of 58L398 MHz. the 
satellite must receive a frequency of 
435 .4945 MHz to transmit at 145.9035 MHz. 
At any point, the sum of the satellite's re- 
ceived frequency and the satelliie's transmit- 
ted frequency is always 581.398 MHz. 

t plink Sliifl 

Since the saiellite must receive a frequency 
of 435.4945, we must transmit a signal that 
allows for the Dopplcr shift. To calculate the 
ground transmit frequency (fg), place the 
satellite receive frequency and ine Vr into the 
Doppler shift equation and solve for^; 

435,494,500 = f g + 3.09 (fg/300,000) 
f^ = 435,490,000 

Thus to receive on 145.905 MHz, you 
would transmit on 43S.490 MHz. The uplink 
Doppler shift is 4,500 Hz down while the 
downlink shift is 1500 Hz up, for a net shift of 
3,000 Hz down. 

You might notice that the total shift is twice 
the apparent shift of the beacon in the oppo- 
site direction. You can follow this rule for all 
OSCAR- 13 Mode B operations: lite total 
shift is equal to twice the opposite beacon 
shift. If the beacon frequency is shifted by 



1000 Hz down, raise your transmit frequency 
by 2000 Hz. 

IF you w anted to put your receive signal on 
145,8 MHz, without Doppler shift you would 
transmit on 435 J98 MHz, However, if the 
beacon is shifted 2000 Hz UP. the transmit 
frequency would be shifted 4(KX> Hz DOWN , 
to 435.594 MHz. 

Mode L and Mode S Rules 

Using the Doppler formula^ you can also 
work out the rules for Mode L and Mode S. 
Mode L is also an inverting repeater (widi a 
translation frequency of 1705.356 MHz) with 
a rule similar to Mode B: the total shift is 
equal to 1.9 times the opposite beacon fre- 
quency shift. If the beacon shift is 3000 Hz 
UP, you must shift the actual transmit fre- 
quency 5700 Hz DOWN. This rule is not 
exact, but it is close enough for government 
work. 

Mode S is a non-inverting repeater fwith a 
translation frequency of 1965. 1 1 MHz) so the 
rule here is a little different: The total shift is 
equal to 1 .2 times the beacon frequency shift. 
If the beacon is shifted 10,000 Hz UP« you 
must shift the actual transmit frequency 
12.000 Hz UP. 

The rules are a result of translation fre* 
quencies, repealer types, and uplink/down- 
link frequencies, and not just whether the 
miKle is inverting or not. 

Let The Computer Do It 
Because Mode L and Mode S rules are not 



exact, 1 have included a simple BASIC pro- 
gram to aid in exact shift calculations. The 
program is also for those of us who can*i do 
simple math. The program assumes you arc 
using OSCAR- 13, 

To use the program, either run the com- 
piled version or load the code into your BA- 
SIC interpreter. The program will ask you for 
your operating mode (B,L,S) and the mea- 
sured beacon frequency. The program will 
then ask for the received frequency that you 
want to wind upon. Your transmit frequency 
will then be displayed along with the relative 
velocity, Vr, 

The program should run on most comput- 
ers having BASIC. The source code and com- 
piled version is available on CompuServe (in 
the Hamnet conference) or from the author 
(in MS-DOS format on 5 'i '' or 3 Vi '* diskette) 
for US $5 .00. If you get the program from the 
author, a more sophisticated version will be 
included with the simple version. Contact 
AMSAT for information on commercial soft- 
ware or join the Hamnei conference on Com- 
puServe. 

OSCAR- 1 3 really adds an exciting new 

mode of communications to the amateur 
world. By monitoring the beacon frequencies 
on the satellite^ you can use these simple rules 
to find your signal the first lime» every time. 
This is especially easy using Mode B since 
your trans mi I frequency shift is just twice the 
opposite of the beacon shift. So have fun and 
happy satelliting! 



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73 Amateur R^dio • August. 1989 45 



Number t7 on your Feedback card 




Jugendelektroniczentrum 

How one Swiss group supports the education of young hams 



by Ruedi Mangold HB9DU 



I have been a ham since 1930. 
Ai Firiii, I did shortwave listen- 
ing, but in 1938 I got my amateur 
license. Then, during WW lU I 
was in the Swiss Army Signal 
Corps, repairing equipmcni. Af- 
ter that I taught physics at the 
Basel technical college. 

Bui we always come back! Re- 
cently, I began teaching amateur 
radio. 30 adults at a time, using 
my excellent physics equipment 
and the college physics auditori- 
um. Candidates for licenses were 
tested by our experts from the 
PTT (like the American FCC) 
from Berne « and they got the 
highest percentage of passing 
grades in Switzerland— 86% of 
them correctly answered the re- 
quired 70% or more of all the 
questions! 

This was, we here all agree, because the 
course included lectures, films, experiments, 
what you call *'handson" training, and visits 
to Swiss transmitting stations. It was a real 
triumph for them, for our FIT is a hard 
taskmaster in ever> respect. 




FIT Rulcji and Regulations 

Some who have worked HB sici!i<ms have 
perhaps thought Swiss hams curt and impo- 
litely short. Please do not think so. It is be- 
cause a ham is likely to be punished should he 
talk more than, say, ten words about the 
weather. The PTT listening, or control, sta- 
tions are severe supervisors* You arc allow^ 
only conversations about technical topics and 
'information of negligible value, for which 
the use of the telephone is not justified/' 
Third party information "is strictly forbid- 
den/^ 

Funhermore, there is no protest allowed 
against any PTT verdict. In the Swiss Consti- 
tution, the PTT is given absolute monopoly 
over all communications. And since there is 
no exact definition of forbidden conversa- 
tions, the Swiss ham. as we say, "always has 
one of his legs in the law courts! '* 

The first license in Switzerland was issued 
to H. Degler in 1926. His call was H9XA. 

46 73 Amateur Radio ■ August. 1989 



Photo A^ From left lo right: Ruedi Mangold HB9Db\ founder and 
spirittts reaor of JEZ: Christine Wirz-v* Plama. president of the 
supporting club; and Christ oph Biel HB9DKQ, technical chief of 
JEZ. (Copyrighted photo by Andre Mueihaupt, BaseL PtMishedin 
Easier Zeitimg: 17JJ988[) 



When the Union of Swiss Shortwave 
Amateurs, the USKA (our version of the 
American ARRL) was formed in 1929, there 

were 35 amateurs. Today we have over 

Testing Rcquiremcnls 

They all passed the tests. For the ** small 
license/* meaning you can send on 144 MHz 
and up {200 W PEP for the first three years, 
then 1 ,000 W PEP), the tests are: 

(1) 20 multiple-choice questions — most 
abom complicated algebraic problems in gen- 
eral elecironics, and on receiving and trans- 
mitting techniques — to be answered within 60 
minutes. 

(2) 20 questions on international regulations, 
codes, and security regulations. 

(3) 10 questions on antenna-building regula- 
tions. (Switzerland is a highly electrified 
country with a rather dense telephone net- 
work^ and severe laws about the proieciion of 
landscapes.) 

For the *'^big Iicen.se/' allowing use of the 
short waves* you also must pass the Morse 
exam. For a tlve-minute period you must 
work at 60 charactcrs-per-minute (12 wpm), 
transmitting and receiving in mixed lan- 
guages with no more than three errors. 



Exam questions change with 
every test, and there is no biK>k of 
past questions you can study. 
Candidates must have a thorough 
understanding of electronics. This 
is why we have courses which run 
for three semesters* two hours per 
week. 

Now you see why my candi- 
dates were so proud of them- 
selves! 

Funiiation of JEZ 

I was able later to have classes 
for youngsters, ages 14 lo 18, 
using my college facilities, 
but having the Ba^l Education 
Depanment pay all of their ex- 
penses. There were nine courses, 
three of them for kids, by the lime 
1 retired in my sixties. And then, 
having seen the very big need 
to help introduce youngsters to the world 
of electronics and amateur radio, in 1974 
I founded JEZ— the Jugendelektron- 
iczentrum, 

Within mi>nihs it was clear that leisure- 
time courses would not be enough and com- 
munity involvement was called for. The loc^I 
radio club, the Funkamateur Club of Basel 
(FACB), pitched in. An unused kinderganen 
building was obtained; it was located on the 
second highest point in Basel, surrounded by 
nieadows where antennas could be erected. 
Ten FACB members put in 1600 hours of 
volunteer time and installed electricity and 
plumbing. The town^s chemical companies 
donated furniture, a chain-store company 
(the Migros) donated tools, and factories 
gave dozens of measuring instruments, in- 
cluding multimeters, spectrum analyzers, a 
sheet metal bending machine, and lathe and 
turning tools. The tibrar>' stocks 10 different 
European and US electronic journals, and 
there are drawers that contain over 8, (XX) 
different components. In this self-service 
system, students pay for what they use when 
they leave the workshop, 

By the mid- 19805 we were offering courses 
(much less expensive than the usual S230 for 
school boys to learn about ham radio) in a 




Photo 8. JEZ antennas: twenty meter nmxf 
with beams for 2 meters mid 70 cm: satellfte 
antennas and a Windam above for 40/^ 
meters: Versatower with DJ2UT beam in 
foreground. Not visible: Meteosat and A TV 
receiving and tnmstniiting antennas. 



variety of subjects in 
the field of clcciron- 
ics. As of 1988, some 
40 youngsters were 
taking courses week- 
ly. About 20% of 
them will become m* 
tercsted in ham radio 
and the others will get 
very good jobs in the 
electronics industry. 
We don't just make 
amateurs, we make 
motivated youngsters 
for high tech fields. 

Because the re- 
sponse to our center 
was so great, and the 
lask too much for 
volunteers from ihe 

80 member FACB, we had to organize 
more formally. We now fiinction with the 
government giving us rent-free space and 
an annual contrtbution of 55,000 Swiss 
francs (about 539,000), and we have a 
supporting club, the **Tragerverein JEZ," 
presided over by a prominent Basel Member 
of Parliament, Mrs. Christine Wirz-v. Pian- 
ta. We have private donations which also 
amount to 55,000 SFr. and a working crew 
which includes six instructors, and other 
volunieers who help keep the center tidy 
and the equipment working. Chnstoph Biel 
HB9DKQ is the JEZ chief instructor now, 
and 1 am a helping hand for him. (I sometimes 
say that HB9DKQ is now the conductor. 




photo C At left are resistors and condensers; window shelves hold 
spectrum analyzer. Also shoHTi are frequency generator (10 Hz to 12. 6 
GMz}r frequency comiiers, and oscilloscopes. 



and ! am only the semiconductorf) 

In A Word: Meaningful 

We have now a serious learning center with 
a friendly atmosphere. The youngsters can- 
not just come and go as they wish - We have a 
nice cafeteria and a well -stocked library* and 
the best of equipment and the best sponsors. 
The electronics industry has been saying to 
me that we provide them with the best techni- 
cians. 

I am afraid nolK>dy often hears the HB9DU 
call any more; l am too busy. But in my 
choice beiwcen being an Elmer for 40-50 
youngsters and a DX chaser, I have taken the 
route that is eminently more satisfying. . 



HRT-I 



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Marvann<WB6YSS) 



73 Amateur Radio • August, 1989 47 



Number lidn yc^urFeedb^^k card 



Need FM? 

FM demodulation circuit for older receivers. 



by Walter Symczyk KB2BQK 



Phascd'locked loop (PLL) i meg rated 
circuits can enhance the capabilitteiv of 
older equipment. With the recent increase 
in FM activity on the 6 and 10 meter bands » 
I began looking for a way to monitor this 
activity. My station did not support either 
band. ] nionitored the 6 and 10 meter bands 
with my Hammarlund HQ-170-A. but this 
receiver didn't demodulate FM. 

The Mod 

I decided to use a PLL IC to demodulate 
FM signals from the IF strip of the Ham- 
marlund. The IF frequency 
of the Hammarlund HQ-170-A 
is 455 kHz. A phono plug on 
the rear of the receiver allows 
access to the IF strip. The IC 
chosen for ihis taj^k was a 
NE-565'N which has a fre- 
quency range from 0.001 Hz to 
500 kHz. 

This IC, readily available for 
less than live dollars ^ consists 
of a phase detector, VCO, and 
amplifier. For projects with 
receivers of different IF fre- 
quencies, you may need a 
different IC. For example, the 
NE-560-B has a frequency range of I Hz to 
15 MHz. (Please note that ihe internal con- 
figurations and pinouts differ on these ICs, 
but you can otherwise upply the concepts in 
this article.) 



HoH Demodulation Occurs 

The operation of this IC is con I rot led by 
the following external componentN: CI 
and Rl control the free running frequency 
of the VCO, and C2 controls the cap- 
ture range (the range over which the 
PLL acquires phaisc lock). To demodulate 
FM, set \hc free running frequency of 
the VCO to the frequency of the receiver 
IF, and set the capture range to appn>ximaie- 
ly the w idth of the signal you w ish to demodu- 
late. 

Connect the VCO to the phase detector 
through pins 4 and 5. Connect [he input sig- 
nal at pin 2. The demodulated output is 
presented at pin 7; it is the correction voltage 
which keeps the VCO locked on the input 
signal. In other words, the phase detector 
compares the input signal with the signal 
generated by the VCO and generates a 
correction voltage for the VCO, This correc- 
tion signal is amplified internally and fed 
back to the VCO to maintain the lock. It is this 
correction :^ignal which provides the demod- 
ulated output. 

The design formulae used with the 565 
ar^: 

48 7$ Amateur Radio • August, 19SS 





^^^^^^^•'^Mr ' ^4^^^p 





Pftow A, As^etnMed FM demoduiuior. 



Parts List 



U1 NES65N 

C2 0.1 |jF ceramic 

CtA tOOpFctramic 

GIB 27 pF ceramic 

C3 0.001 ^iF ceramic 

Rl 10k variable 

R2 5230Q 



C t A & CI B used in parallel 
to obtain 127 pF 



\H¥\il FROM 



Aj T 



O.ImF 



T 



iQ 



Rl 
lOK 



jfcC? 



R2 tea 

■ )h- 



^^ 



EF 



-• +9V 



CI 

IN PAftaLLtL 



>v 



«UO}0 OUT TO 
AMPLiriER 



fC3 ISREOulRED TO ELIMINATE PQ'S^IQLE OSCHLATlON \H THE 
COMTROL CURRENT SOURCE 



Figure L Schemanc of she FM denuHitdator. 

Frcc-mnning frequetKy of 
VCO:fo=^1.2 4iRl)(Cl) 

lock range f^ = ±8fD^^cc 

capture range f ^ — ± nhV '^F'^ 
where r = (3,6 X fO^)CC2) 

Now for the real world: Armed onlv with a 
poorly supplied junk box. IC spec sheet, fre- 
quency counter, ARRL Handbook and a 
Heaihkii HO-5405 station monitor scope, I 
first assembled an oscillator circuit using a 
555 timer IC, This circuit was rtinning at 
about 350 Hz. Then I set up the 565 to lock on 
the signal generated by the oscillator. I ob- 



served all the inputs and outputs until I was 
comfortable with the operation of the 565 IC. 
What I learned at this stage was invaluable for 
later debugging. I highly recommend that 
anyone doing a project of this nature go 
through this exercise. 

Figure i is the circuit I came up with, 
and which I am currently using. The com- 
ponent selections were all compromises 
based upon what was in my junk box. There- 
fore* in many areas there is room for opti- 
mization. I constnicied and tested the circuit 
on a breadboard. When I fmished playing 

with it, I moved it to a PC board 
using ugly construction. 

Solving the Problems 

The first problem I encoun- 
tered was insufficient signal 
strength ai the phone plug IF tap 
of the HQ-170'A. To solve this 
problem, I changed the tap 
point further down the IF. strip 
where a stronger signal was 
available. 

The second problem was tun- 
ing the circuit. 1 accomplished 
this by setting the 565 VCO free 
running frequency with a fre- 
quency counter to 455 kHz. adjusting Rl . To 
do this, remove the jumper between pins 4 
and 5. and ground the input pin 2. 1 also used 
a filter capacitor which allowed a capture 
range of ± 13 kHz. I connected every ihing up 
to the Hammarlund. When I was satisHed that 
the circuit was locking on signals (this re- 
quired some fiddling with R h, I replaced the 
filter capacitor with one w hich provided for a 
capture range of ±4,2 kHz. 

After everything was running, the audio 
required external audio amplification. In re- 
gards to pcrtbrmance of this circuit I ob- 
served that signals received with a strength of 
S-5t as indicated by the Hammarlund 's S-me- 
ter, are full quieting. I believe that the circuit 
could also be improved by a belter choice of 
componctits and the addition of an external 
amplifier stage prior to the PLL, 

If you have an older receiver and you can 
spare the cost of the IC. I think youTl find this 
an educational, entertaining, and rewarding 
project. 



Bibliography 

Berlin, H.M,, Design of Phase'Locked 
Loop Circuits with Experiments, 
Howard W. Sams & Company, Indi- 
anapolis, 1988. 

Th^ ARRL Handbook for the Radio Ama- 
teur^ American Radio Relay League, 
Newington, 1985. 



Number 1 9 on your Feedback esrd 



10 GHz RF Preamp 

A building block toward a complete 10 GHz transceiver system 



by C,L Houghton WB6IGP 



the amplifier may become useless. Lead 
length is critical for proper operation. 
See Figure 1 for the schematic and parts 
placement. 

The Teflon^" PC board is 0.031" thick, 
with a dielectric constanl of 2.5. You wilJ 
need Teflon sttx:k because other materials 
will not perform at microwave frequencies. If 
you can not fmd any Teflon, or jusi don't 
wish lo make our own, I will provide the 
etched PC boards and /or a minikit of parts. 




Construct an amplifier for the 10 GHz 
microwave band? How about 18 
dB gain and 3 dB noise figure at 10 GHz? 
Does it sound impossible? Well, h isn't! 
San Diego Microwave Group members have 
conHiructed several of these amplifiers and 
all have worked quite welL Thanks to Clark 
Bishop WB4PQD, who designed this stable. 
high performance* dual-mode amplifier for 
10 J2 GHz, and who is allowing us to 
publish the design for amateur use. 

Preamp Cortstniction 

The amplifier described here 
has been used as a receiving 
preamp! i Tier and as a transmit 
amplifier, with appropriate RF 
relay switching. Construction of 
this amp is somewhat delicate 
due to its small printed circuit 
board and components. The fin- 
ished PC board is I ^A " by 1 " (see 
Photo A). 

Mitsubishi's low-cost (about 
$15 each) Gallium Arsenide Field 
Effect Transistor (GaAsFET) 
MGF-1402 is central to the pre- 
amplifier's design. It has gold Photo A. Close-up showing (he 10 GHz preamp on top of an lC-02 
metalization strapping over the battery box for ^ize comparison. The ampUf^er uses two MGF-! 402s 
ceramic case, connecting the ami boasts ortly 3 dB noise figure and IS dB gain. 
two strip line opposed 
source leads. Most I T 

importantly, this 
metalization reduces 
the total inductance 
of the source leads 
necessary for good 
operation at 10 GHz. 
When ordering, be 
sure to specify the 
full gold metalization 
over the case connect- 
ing the source leads 
together. 

In other designs, the 
emitter or source leads 
are bent down and 
over to connect to the 
rear ground foil. At 
lower frequencies, this 
works well, bu( at fre- 
quencies above 5 
GHz, a very small in- 
ductance in the leads 
will give low gain and 




Photo B. N61ZW's W GHzpre-amp. GoAsFETs are mounted itpside down, under the "W" 
and ^'N*' in the catlsigns. Coax connectors are SMA. 



The amplifier is a two-stage device requir- 
ing a small power supply with negative bias 
and positive drain. Current demands are 
light. The external power supply that I built 
furnishes a bias of —1 volt DC and drain 
voltage of +4,5 volts. You could use an AA 
battery for bias and an adjustable regulator 
for the drain voltage (see Figure 2). 

Building the Power Supply 

J decided to build a pow er supply that pro- 
vided sequencing protection, as 
Ray W6AMD suggested. By 

putting a series pass transistor in the 
positive input circuit, the positive 
voltage will not activate until the 
bias supply is operating at fiill po- 
tential (see Figure 3), I have used 
this protected power supply for 
months* and it has proven reliable. 
It runs from a 12 volt supply. The 
negative power supply is enclosed 
in a small 24-pin DIP package and 
looks much like a large EPROM, 
The transformer-isolated power 
supply i.s regulated to -9 volts with 
40 mA of current available. 

We only need a few mA, so the 
power supply loafs in this applica- 
tion. Part of the negative supply is 

voltage divided to ihe 
-1.2 volts to feed the 
gate bias circuitry. 
This requires ver>' lit- 
de current- The main 
—9 volt output is fed 
to a series current lim- 
iting resistor in series 
with a 6 volt zener 
diode, which in turn 
feeds the emitter of a 
2N2222 NPN transis- 
tor. 

Tie the collector of 
the 2N2222 to the 
base of the 5 Watt dis- 
sipation PNP pass 
transistor which con- 
trols the input of the 
LM-317 positive ad- 
justable regulator. 
When you apply + 12 
volts to the power 
module, the negative 
power supply turns 



73 Atnateur Radio • August, 1989 49 



on, producing —9 volts output. This negative 
voltage passes through the 2N2222 switch- 
ing transistor, and turns on the base of 
the pass transistor, a 2N5322. If for some 
reason the negative voltage isn't high enough 
to overcome the series resistor and zener, 
or if it fails to come on at all, the positive 
supply will not come on, either. This pre- 
vents the positive supply from applying 
voltage with zero bias on the FETs. There 
are lOOQ in the drain leads to tiinher protect 
the FETs, so this is just additional protection. 
More than 6 voks can destroy FETs, so this 
rating should never be exceeded. I placed 
5.6 volt zencrs in bodi the negative and posi- 
tive power supply outputs to prevent any 
possible problem. I mtxlified the PC board 
to accept 5 Watt zeners, which should 
fold down the power supply in case of over- 
voltage- 

Mounting the Components 

The components to be mounted on the am- 
plifier board are all chip type resistors and 
capacitors. The chip resistors, of which you 
nee<! four, are lOOQ. Three 1 pF ATC-lOO 
type chip capacitors are used to connect the 
input, output and interstage coupling. We 
have used values up to 2 pF with little change 
in performance. The bypass capacitors, of 
any value from 100 pF to 1000 pF, are chip 
type. 

Prepare the PC board by cleaning it with 
fine steel wool. Apply a small dab of liquid 
rosin to the spot where you want to solder a 
chip component. This will hold it in place 
while you solder. You can use a toothpick to 
position the chip resistor or capacitor and to 
hold it down so you can solder only one end of 
the device- Then you can solder the other 
end . A chip soldered on both ends is difficult 
to reposition. 

By the way, I recommend a temperature 
controlled, low vohage iron, such as a Welter 
WTCPS soldering station. They're ground- 
ed, a requirement for working with the static- 
sensitive GaAsFETs. If you don't have one, 
unplug your soldering pencil and ground it 
when soldering GaAsFET devices. 

Position and solder all chip capacitors and 
resistors on die front face of the PC board. 
Solder a grounding foil around the outside of 
the PC board edges. Cut out the top foil 
where the SMA coaxial connectors will be 
mounted, to give clearance to the center con- 
ductor of each SMA connector. Solder the 
ground foil and the ground part of each SMA 
connector together, on top of the board. This 
makes a short ground connection to the outer 
perimeter of the lop of the PC board, and a 
solid connection to the rear ground foil 
surface. 

Now, make the cutouts for the FETs in the 
circuit board and rear ground foil^ clearing a 
hole about 0. 100" square to fit the FET. The 
case size of the FET is specified at 0.071 ". 
The hole should allow easy entry of the FET 
on the PC board when you're ready to solder 
the device. The FET is mounted upside down 
on the PC board (see Photo B), allowing the 
top of the FET {part of the strip line source 
connections common to the FET) to be 

50 73 Amateur Radio • August, 1989 




', .^-: A. - .*■ I--,.'.' ., 




Photo C. Rear view of the 10 GHz preofnp, showing the mounting arrangement of bias 
adjustment pots, and the brass bar which strengthens the soft Teflon PC board. 



JOdS GASN 
MGF-1402 



[pF 
RF IN >^^j- 



:ioon 




ipF 



iOdS GAiW 
MQf'\4Q2 



IpF 



loon 





^ 



-CRFOUT 



^ooa 



fOOil 



/T? 



A jfj 



* 



m 




* /77 



* ^ BYPASS 100 pF TO lOOOpF OK 



IpF 



GATE 



INPUT 



lOOH 



7. 




x2 



BVPASS 



T. 




DRAEN 



lf^F 



^\ 



OUTPUT 



\QQa 




-^h-P 



8YPASS 




ZJ 



IVDC 




O). 



4.5VDC 



GATE BIAS 



ORAfN BIAS 




'A 



i - TRACE GROUWDED TO REAR FOIL 



Figure L 10 GHz preamp schematic and pans placement diagram. 



ih 



LM'Bir 



25V 



220 






X. 



10;! F 

25V 



/7? 



i!EN£R 



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#1 #2" 



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♦ 62^ 



* IK POT SET FOff 6^4 ft WILL GIVE +4 5V0C OllT#UT 



I ON AMP BOARD BACK 



GATE 



001 



FB 



I 







-=- I 5V 
- "AA' CELL 



K)ic 



rn 



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GATE 

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* BY^^ASS ON Ff?OAJT 
or PC BOARD 
lOOpF ro lOOOpF 

FB T FERRrTE gFAD 



NOTE ^ POTS ADJUST FI^OM 

to -O 75 V NEGATIVE giAS 



Figure 2. Power supply wiih baueryforthe 10 GHzpreamp, 



+ i?vo Co- 
in frUT 




IH— 



ID^F 
Z5V 



/w 



62V 
ZE^JER 




220 



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MAX • 



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01 



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fri 



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Df^Aini 



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♦ -a SV 

DflAIISi FEED e- 



3f 



J 



Figures. Power supply for preamp. Supply prtmdes sequencing protection. Vie schematic 
heftnx' the power supply schema! ie shows where the power supply leads attach to the amp hoard. 



soldered to the rear ground foU, This makes 
the short source leads required for this 
frequency. Do not mount I he FETs now. 

NexL mouni the bias adjust circuitr>\ two 
lOkO pots, on the back of the board. Pass the 
wiper of each pot through a small hole in 
I he ground plane so that it contacts the bias 
fccdpoint for FET^l and #2. The opposite 
end of the adjustable potentiometer is 
grounded, and the high end is lied common to 
each other with a 10k 14 Watt resistor in 
series with the bias supply. Place a small 
insulator under the pots to prevent the top 
negative supply point from possibly touching 
ground with any downward pressure on the 
pot. Tie the two drain lines common, on the 
back of the board. 

When ail components arc mounted and the 
FET cutouts made, check the board careful- 
ly* then insert the GaAsFETs, one at a time, 
into the board. Use a grounded soldering 
station, and don't forget to ground yourself to 
the work piece. A wrist strap of high resis- 
tance, but sufficient to discharge any sialic 
from yourself, is available from many deal- 
ers. This is necessary to prevent damage to 
the sensitive FETs. If you take these precau- 
tions you should not have any trouble- Just 
work slowly and carefully, and keep all com- 
ponents grounded. 

Final Check 

in this last stage, pre-sei the bias pots to 
maximum resistance, or maximum negative 
bias, to limit the FETs* drain current. Apply 
negative bias to both FETs, and \^ hile watch- 
ing the first stage with a current meter ( 1 used 
a to 100 mA meter), adjust the associated 
bias pot to a drain current reading of 10 mA. 
(For the preliminary' check, you might want 
to Stan vs ith a positive DC voltage somewhat 
less than 4 volts.) 

The first stage current of 10 mA is consis- 
tent with minitTium noise (Igiire according to 
the gain versus noise figure curves. Stage two 
is adjusted in the same way. except that 
you should adjust for a current reading of 
20 mA. Higher current is not necessary, as 
the device is operating at optimum per- 
formance at this current level. For fine tuning 
anomalies, you may affix small pieces of 
copper to a ttmthpick and move around the 
traces of the PC board. We did not perform 
this step because we were satisfied with the 
gain we obtained, it was stable and vcr> near 
optimum. 

When you are satisfied with the oper- 
ation, you can adjust the bias to minimum 
current and re-set the positive DC supply to 
4.5 volts. Go through the same procedure 
to set current levels. Do not apply DC 
voltage, negative or positive, above 5 volts 
because 6 volb will destrov the device. Go 
slowly, don't rush, and think your operations 
through. You can measure three times, but 
you can cut only once* 

After the final checkout, put a short piece 
of scrap brass on the back of the PC board, 
over the soldered connecuon for the FET 
source case lead {see Photo C). Mount the 
brass to clear the other parts, and solder it 
between the two SMA flanges and the ground 

73 Amateur Radio • August, 1989 51 



foil. This will reinforce the Teflon PC board. 

House the amplifier in a suitable, shielded 
container along with the power supply (see 
Photo D). 

Performance 

From use» we know the amplifier is quite 
stable* with a good performance record. 
Most of the units we built varied due to differ- 
ent construction techniques, but ihe\ alt gave 
close to 18 dB gain. The amplifier as both a 
receiving and transmit amplifier gave very 
good results. In Eransmit. the maximum out- 
pot we obtained was +8 dBm as read on my 
HP-431 power meter. Kerry N6IZW and I 
feel that this is due partially to the fact that the 
lOOQ drain resistor on the output stage limits 
the device. We plan to try changes by setting 
bias and replacing the lOOQ resislpr with a 
RFC This will require funher experimen- 
tation. 

We made the relay switching scheme with 
four relays which happened to be the only 
microwave relays in our junk box. You can 
use other types, but check their loss, as the 
ones we used were less than 0. 1 dB connec* 
tion loss per coniact. Cross isolation was ex- 
cellent: loss from coupling from one operated 
side to the non-operated side was in excess of 
50 dB. All interconnections were made with 
0J41 coaxial hardline and SMA coaxial con- 
nectors. 

The outline in Figure 4 shows our complete 
SSB system for 10 GHz. Other major parts of 
the system are the mixer and phase locked 
microwave oscillator. We obtained the latter 
from surplus. You can buy or build the the 
mixer. In another article, I will cover these 
items in detalL 

Concttision 

Construction of this amplifier will give 
you a very good preamplifier and versatile 
device for 10 GHz microwave band opera- 
tion. We have also used this device on our 
spectrum analyzer lo improve system sensi- 
tivity, 

PC boards for the 10 GH2 amplifier are 
available etched and ready for mounting 
parts, with the ground foil, for $10 each 
postpaid. A kit with the chip resistors and 
capacitors^ SMA connectors (2), ground foil 
and PC board, is $20 postpaid. The switch 
mode power supply module is S5. Specify 
5 volts or 12 volts input. The MOP- 1402 
GaAsFET is available from Microwave 
Components of Michigan, 1 1 21 6 Cape Cod 




Figure 5. FCB foil diagram for 10 GHz 
preanip. 

S2 73 AmatBur Radio • August, 1989 



Sl , Taylor, MI 48180. TeL (313) 94! 84m 
(evenings only). Or call any distributor who 
carries Mitsubishi GaAsFETs. Cost is less 
than $15 per device, I would be happy to 



answer any questions pertaining to mi- 
crowave or related subjects. Please send an 
SASE for a prompt reply to Chuck Houghton, 
6345 Badger Lake, San Diego CA 92II9.\ 




Phow D. 10 GHz SSB station WB61GP uses 24 SMA canneaors and 4 SMA SPOT 18 GHz 
relays. Preatnp is inside the small haihluh-capaciior-lookdng shielded box. The large unit in [lie 
rear is the phase locked 10 GHz oscillator. See Figure 4 for block drawing. 



TO/FROM 

ANTEUMA 

SYSTEM 



RLG -SMA -TYPE 

'S-' 2T86' 

SURPLUS coax RELAYS 

4 EACH REQUIRED 



fO 3686Hz 

FILTER PATCH* 



SMA 



SMA 



PATCN#£ 
SMA 



10 GH2 ^**1 
PRE-AMP 
Z EA/MGFI402 ^j: 
£0/dS GAJM lI 




I- 



SMA 



10 GHz 

MiXED OUTPUT 

APPROX -IdBM 



f TRANSMIT COAX 
* RELAY ENERGIZED 



AMP'tt^ 



PATCH 



W^*'& 



AMP-OUT 



/7? 



t t 



t 



MORMAILY COMMON NORMALITY 
CLOSED OPEN 



+24V0C TO 

TRANSMIT 

OPEN ON 

RECEIVE 



MIXER 



RF 



l-F 



SOOmW MAX 



LO 



t 



+ JOCJ0M 
INJECTION 



BR\CK 

OSCILLATOR 
10, 22 3 GHz 
6 Hi 



BdB 
PAD 



2 METER U-F} 

M T 
145 M Hi 



LO + IF * 10 aSBGHr 



Figure 4. 10 GHz switching , for receive and transmit. 



Number 20 on your Feedback card 



IF Shift , Cheap 

Easy IF shift add-on to your older rig. 

by Terry F. Staudt, LPE, W0WUZ 



About J 980, passband tuning, or IF shift, 
was one of the first goodies to upgrade 
the transceivers of the late '7Qs in the A, S, or 
MK n versions- Most people with the earlier 
sets just figured h was another of life's insol- 
uble problems, and let it go at that After 
looking at several schematics, I came up with 
a coup. Not only is it possible to insert IF shift 
in these sets, it's easy and costs less than five 
bucks! 

Vm going to show you how terribly simple 
it is to do. The only odd part is an outer tuning 
ring, which you can get from your manufac- 
turer for a little over a dollar, if you want 
everything to match. Otherwise, anything 
will do. 

IF Shift— What It Is 

IF shift is simply a tuned circuit that uses a 
varactor diode, such as the Motorola MV 
1872, or a general AFC unit made for FM 
home receivers. The circuit is in the sec- 
ondary of (usually) the first IF transformer, 
the original components being re-connected 
to the far side of the added crimmer capacitor. 




1st i^FT^IO-^P^ 

^ m- Zi>d l-F 



Al5-9qpF 



J/SW 



TO MAINTAfcM VARACTOR BIAS 



Figure I. Schematic for the IF shijt circuit. 

The two 2200 resistors are there to prevent 
failure from a bad varactor or the lOk linear 
pot parked at the far end. 

Fm using a 25-year-old Galaxy 5 MK 11, 
and the circuit works wonders, I got a * *finger 
ring,'* as used on the RF gain at a hamfest, 
for a perfect match. 

Reeipe for a Tuned Circuit 

Choose which control would be suitable, 



get the value from the schematic or measure- 
ment, and go to a parts house. Have them 
make you up a dual-ganged pot with the origi- 
nal value as the center control, and a 10k 
linear pot as the outer ring. Pick up the varac- 
tor, trimmer cap, and two 2000 resistors. 

Assembly and Adjustment 

The schematic in Figure 1 is generally sat- 
isfactory for universal application, After in- 
stallation, when you have taken an S-meter 
reading on 10 meters, you must make two 
adjustments. You also need to establish a 12 
volt DC "pick-up*' point. 

First, with the new pot at 50/50, adjust the 
IF transformer for the highest reading. Sec^ 
ond, adjust the trimmer cap for the same 
S-meter reading as before. Resist the tempta- 
tion to go for more, as it would degrade the 
selectivity. Make these adjustments and the 
"benchmark*" reading with the unit's cali- 
brator signal. I chose 10 meters to avoid 
fooling around with a 20 dB over 9 reading. 

So simple and yet so useful— don't know 
why I haven't yet seen it in prim! 



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73 Amateur Radio • August, 1989 53 



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Figure 5. Quarter-wave phasing stub consiruaion details. 



terminating resistor should be changed from 
50Dioal>Qui lOOQ. 

Because of the higher input resiHtance, 
wind a a toroidal matching transformer to 
match the 500 value at the transceiver, [f 
possible, place these transformers at the lops 
of the masts at the feedpoints. If this is im- 
practical, place the transformers al the feed- 
line inputs with tolerable standing waves in 
the lines. Again, losses arc low at the.se fre- 
quencies* 

Physical Layout 

Suburban plot limitations (about two-thirds 
of an acre) demand dimensionai compromis- 
es. Figure 6 shows the original 2*ckmem 
phased array for each dipole. The ma.si is 
assembled from aluminum irrigaiion tubing 
as described above, and the suppon posis are 
2 W* (Ld.) galvanized steam pipe. 

The radiation capture area may greatly 
increase if the halyards, which are almost 
a quarter-wavelength long, could suppon ra* 
diator extensions. For example, if each hal- 
yard supported a half-wave element fed in- 
phase froni the end of the corresponding 
radiator* wc would have diree half-waves in 
phase, instead of a half-wave basic radiator* 
Two of these makes up the 6-clcment phased 
array. 

For this, I put together the quancr-wave 
phase reversing stubs, and connected them as 
shown in Figure 4. Since I had limited space, 
however, I couldn't extend the end sections 
the full 72 feet, I foreshortened these sections 
by adding inductive loading coils beyond the 
ends of the quarter-wave stubs. To reduce 
inductive loading and decrease ground losses 
due to peneiration by the high E-fields at the 
ends of the radiators, I turned these eitten- 
sions upwards to form vertical terminalions 
above Ihc suppon posts* I achieved this by 
clamping lO-fooi lengths of 2'*-PVC (i.d.) 
pipe against the support posts. 

The coils were commercial units, 2*j6" in 
diameter. They slipped over and were 
supported by these pipes above the suppon 
post tops, 8'<6-foot long CB whips mounted 
on caps at the tops of the pipes terminated 
these extensions. See Figures 7 and 8 for 
details. 

Again, the four quarter- wave phase revers- 
ing stubs were made from RG/8M Mini* 
Foam coaxial cable* I adjusted the lengths to 
resonance with a noise bridge. Due to the 
slight variations in dielectric constani, these 

54 73 Amateur Radio • August, 1989 



F£ED 

POINT 



RADIATQP 
60' 



RADIATOR 
60' 




HA LY A ft a 



HALYARD 
NORTH 

syppoRT, , 



SOUTH 

SUPPORT 

POST 



V 7/ / / 



Figure 6. Original h%'a-elemeni phased array. 



POl«iT 



RADIATOR 

6o: 



VeRTlCAL 
T£R«|**AT10*iS 



hfORTH 

SUPPORT 

POST 




SOUTH 

SUPPORT 

POST 



/ ///////// ^ //////////;/// ^ ////////// / -rr-/ - ? 77 



Figure 7. Modified array using inductive coils and vertical elements at the tenmmuions. 



lengths varied from 45 feet, 10 inches to 46 
feet, 2 inches. The feed line polarity was such 
that, in this installation, the center conductors 
fed the south sections of the radiators, and the 
shields fed the north sections. 

Settiiig the Coiis 

First, I checked the cast and west dipoles 
for proper resonant frequency with the 
stubs and terminations in place, but with all of 
the spade lugs open. Then I connecied the 
southeast stub and lerminaiion, and adjusted 
the southeast coil using clip leads until the 
resonant frequency was as desired (3.955 
MHz in this case). For these measurements, I 
used a noise bridge al the input end of the 
feedline. Resonance occurred with 27 %- 
turns on the coiL The corresponding input 
resistance measured about 600- 

Next, I connected the nonheast stub and 
termination and adjusted the nonheast coil 
until T again reached the desired resonant 
frequency. This occurred with a northeast 
coil of 22 ^4 -turns. The input resistance mea- 
sured 11 on. 

r adjusted the west radiator system in the 
same way to yield the COCOA-3 arrange- 
menL The measured resonance values were 
similar, with slight variation in coil turns and 



resistance^ probably due to local near*field 
obstructions* 

Toroidal transformers were wound as 
shown in Figure 9 to correct for mismatches 
in impedance and phase between the two mdi- 
ators, and between source and radiator. The 
positions of the tap, X and the preliminary 
value of the capacitor, C which compensate 
for the inductive reactance of the transformer 
windings* were determined by noise bridge 
measurement using a load resistor of 1 lOO. I 
completed the tlnal trimming adjustment of C 
using the antennas as loads. 

Results 

After completing the resonating adjust- 
ments, I measured the SWR for each of the 
combinations corresponding to the seven po- 
sitions of the phase controlling switch. The 
reflected indication was le.ss than five percent 
of ft] 11 scale for each of the combinations. 
This is far below 1.5:1 SWR for all settings. 
For the two separate COCOA-3 radiators, the 
indication was less than two percent of full 
scale. 

The performance of the array with fore- 
shortened radiators was evaluated in .some 
detail using a receiver equipped with an accu- 

mniinuedonp. 78 



Aerial view 



Hmnher 21 on your Feedback canl 



Arli^ Thompson W7XU 
Route 7, Box 52 
CoitonSD 57018 

Testing Coax 

One of the most commonly 
used, and sometimes abused, 
items around a ham shack is 
coax. While open-wire lines cer- 
tainly have their place, most of us 
use coaxial cable in one form or 
another to feed our antennas. Al- 
though it's relatively expensive, 
coax often doesn't receive much 
respect or attention once it has 
been installed. If your antenna 
doesn't seem to be performing the 
way it used to. perhaps the prot>* 
lem lies with the feadline and not 
wtth the antenna itself. Is your 
coax as good now as the day you 
bought it? How do you know? 

None 100% Etficient 
TheyV© atf losers. Regardless 



Antenna News 

of price, no coax Is perfect. They 
ail have losses that arise from a 
number of sources. Two causes 
are the resistance of the wires 
making up the cabte, and the ef- 
fects of the dielectric material. 
These losses increase with the 
Togarithm of the cable length and 
are expressed m decibels of atten- 
uation per hundred feet of trans- 
mission line. 

For any given coaxfal fme, the 
losses increase with frequency 
and SWR. Figure 1 shows typical 
frequencyHiJependant losses for 
a variety of common lines; Figure 
2 shows increased losses due to 
standing wave ratios greater than 
1:1. The losses caused by elevat- 
ed SWR arise from increased 
losses in the conductors and in 
the dielectric. Conductor losses 
increase because currents are 
higher in lines with high SWR. 
Such lines also have increased 



voltages, thereby increasing 
dielectric losses. This situation 
may be expressed mathemat- 
ically or» as in Figure 2, in graphi- 
cal form, 

Coaxial cable losses tend to in* 
crease with the age of the cable, 
particularly when ihe cable is 
used outdoors or is somehow 
abused. Cables equipped with 
PL-259 (UHF) connectors are par- 
ticularly susceptible to water dam- 
age since that style of connector is 
not waterproof. Other environ- 
mental contaminants can affect 
coax by entering through the ca- 
ble's outer coverirrg. This is espe- 
cially likely if the cable has a 
polyvinyl chloride outer jacket that 
is not noncontaminating. Try to 
use a noncontaminating jacket if 
you're going to bury the transmis- 
sion line. 

Measuring Looses 

Ideally, check for coaxial cable 
losses when you first buy it, then 
recheck it at intervals thereafter, 
Rechecking every two years 
should be sufficient unless there 
is an obvious decrease in trans* 



mission line performance. 

Testing new coax is relatively 
simple. All you need is a source of 
RF (your transmitter), a dummy 
load whose impedance is equal to 
the characteristic impedance of 
the line, and a wattmeter. With the 
wattmeter at the transmitter end 
of the line and the dummy load 
attached at the far end, apply pow- 
er and take a wattmeter reading 
(PI). Remove the power, move 
Ihe wattmeter to the dummy load 
end of the cable, and then . without 
making any changes at Ihe trans- 
mitter, reapply power and note the 
new wattmeter reading {P2). You 
can detemiine the Ime foss from 
the equation: dB = iO!og{Pl/P2). 

For example, assume you have 
200 feet of RG-8 and you set up 
the test as described at^ve. Let's 
say you apply RF to the coax and 
measure to wans of power at the 
output of the transmitter You then 
move the wattmeter to the dummy 
load end of the line and reapply 
power. Now the wattmeter reads 
8.3 watts. Using the equation 
above, dB loss = 10 log (10/S.3) = 
O.a dB for 200 feet of cable. The 



10,- 






< 




flO so fiO 70 (0 to 100 



FREQUENCY iUHt) 



4O0 40D fiOO 70D tlOO 

eoo 1000 



J 



Figure h Attenuation In decibels per 100 feet for various common transmission fines (from the ARRL Antenna Book/. 

73 Amateur Radio • August, 1989 55 



m 



loss tor 1CX} feet will be half of that, 
Of 0.4 dB. Referring to Figure 1; 
you can see that the attenuation 
equals ihe specified value at 
4 MHz. 

Now let's assume that you have 
installed your coax, soma time 
has passed, and you wish to con- 
firm that the cable is still working 
as well as it should- You could 
bring the coax back into the house 
and relest it using the method de- 
scribed above, but that would not 
be very convenient *f the feedline 
is securely fastened to the side of 
your tower. Another possibility 
would be to carry a dummy load 
and a wattmeter lo the end of 
your feedline and go through the 
above procedure. Neither method 
is particularly convenient. Are 
there any alternative methods of 
measuring feedline losses? The 
answer is yes. 

Other Ways to Measure Loss 

One method that has appeared 
In the ARRL Antenna Book in pasi 
years is to create an infinite SWR 
at the far end of the transmission 
line and then measure the stand- 
ing wave ratio at the mpui end. 
You can produce this infinite SWR 
by shorting the coax, or by creat- 
ing an open circuit. If a line were 
very lossy, it would at least parttal- 
ly "hide" the very high SWR from 
the transmitter. The SWR as mea- 
sured at the input would be much 
(ess than infinite. On the other 
hand, better lines (those with less 
loss) woutd indicate a relatively 
high SWR under those conditions 
since less of the reflected power 
would be attenuated by the coax. 
Thus, if you knew the SWR under 
those conditions arici had the ap- 
propriate graph (such as curve E 
ot Figure 3) or wonted through the 
mathematics, you could arrive at 
the matched-line loss without 
heroic efforts. 

There are some problems with 
this second method, however. 
See curve E on Figure 3. If 
matched line losses are low you 
will need to accurately measure 
some high SWR values. "High" in 
this case may mean SWRs of 
20;1, 30:1, or even greater. For 
most of us those vafires of SWR 
are all tightly crammed together at 
the full-scale end of our SWR me- 
ters, and it isn't possible to mea- 
sure them accurately- This 
method sounds good m theory, 
but it can Ije difficult to use. 

There is still another way to de- 
termine line losses. Rather than 
creating an Infinite SWR at the far 
end of the transmission line, place 
a load there that creates a finite 



SWR and then measure the SWR 
at the input. The toad may be any 
non-inductive resistor: suitable 
values for 500 coax would be In 
the 150 to 500Q, or Ihe 17 to 50 
ranges (to produce SWRs be- 
tween 3 and 10 to 1 ). With this load 
at the far end of the transmission 
line, you can take an SWR read- 
ing at the input end and determine 
the matched line tosses from a 
graph, or mathematically. Figure 
3 shows matched-line attenuation 
versus measured SWR for stand- 
ing wave ratios of 2:1 (curve A), 
3:1 (curve B), 5:1 (curve C), 10:1 
(curve D) and, as mentioned previ* 
ously, infinite (curve E). 

Here is an example. Consider 
the previous case of RG-8 coax. 
Suppose you used 100 feet of that 
line to feed a 75 meter inverted 
"V" supported near the top of 
your tower. You tested the coax 
before you installed it so you know 
that it originaily showed 0.4 dB of 
loss per too feet at the high end of 
the 75 meter band. A few years 
have passed since then and you 
are curious to see if the line still 
works as well as it once did. The 




LINE \SG^ IN D6.WHEH MATCHED 



Figure 2. Additfonai iine fosses due to SWR greater than 1:1 (from the 
ARRL Antenna Book;. 



m 






til 

3 
I 

o 
w 

X 

o 



10 

8 

6 
5 

4 

3 

2.5 

2 

1.4 

1 

0.8 

0.6 
0.5 

0.4 

— ■ 

0.3 



0.2 



0.14 



0.1 



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6 7 8910 14 20 30 40 5060 80 100 
SWR AT LINE INPUT 



Figure 3. Matched-line loss versus SWR at the input (transmitter) end when the SWR at the toad (antenna) end 
is (A) 2 h (B) 3: t {€} S:t (D) W:t, and (E) infiniie. 



S6 73 Amateur Radio • August 1989 



coax is burled between your 
house and the tower, then taped 
in multiple locations as it runs up 
the side of the tower. Bringing it 
inside for testing is out of the 
question. 

After a bit of consideration you 
climb the tower to your antenna 
and disconnect the feediine. leav- 
ing the connector at that end dan- 
gling in mrdair, Returning to your 
shack, you apply jusi enough RF 
to operate your wattmeter and 
measure the SWR. The needEe 
comes to rest somewhere be- 
tween 5:t and infinity, but with the 
meter scale the way it is you can't 
be much more exact than that. Re- 
ferring to Ftgure 3. curve E, you 
see that the worst the matched- 
line loss t^n be under this set of 
circumstances is about 1.7 dB, 
That's not a major loss, but it is a 
significant change from the value 
you measured when the cabte 
was new. Some authorities rec- 
ommend that you should replace 
a line if there is an increase of 
more than l dB in the rated loss 
per 100 feet. At this point you 
need to more accurately deter- 
mine the matched-line loss before 
you can make a decfsion about 
replacing the line. 

There are two ways to proceed 



at this point. One way would be 
to leave the transmission line as 
is but repeat the SWR readings 
at a higher frequency. From Fig- 
ure 1 you can see that the rated 
attenuation for new RG-8 at 144 
MHz is slightly greater than 3 dB 
per 100 feet. When you check the 
SWR on this open-circuited line at 
1 44 MHz you read a value of 2.5: 1 . 



will continue to use the line for the 
time being. However, you make a 
mental note to test the line more 
frequently in the future. 

Another possible sotutlon to this 
problem would havet>een to place 
a nortinduciive resistor across the 
far end of the feedline. Let's say a 
250D resistor was available, cre- 
ating an SWR of about 5:1 when 



'Tor any 

given coaxial iine, 

the losses Increase 

Witt} frequency 

and SWR/' 



Again referring to Rgure 3, curve 
E, you see that the matched-Nne 
loss IS in the neighborhood of 0.7 
dB greater than it should be at that 
frequency. You decide that al- 
though the losses in the cable 
have mcreased with age, the actu- 
at attenuation on 75 meters {pre- 
sumably slightly over 1 dB per 100 
feet) is still low enough that you 



installed as indicated. Back in the 
shack you measure an SWR of 
3.1:1 at a frequency of 3 J9 MHz. 
Had the line been perfect (none 
are) you woutd have seen an SWR 
of 5:1. Had you done this test 
when the line was new you could 
have expected an SWR reading of 
4:1 . Reading from curve C of Fig- 
ure 3 you find that under the de- 



scribed condftions the matched- 
line loss must be slightly greater 
than 1 dB, or approximately 0.7 
dB per tOO feet worse than it was 
when the coax was new. Agdin, 
the coax is showing signs of aging 
but it wilt stiil work in this applica- 
tion. A similar increase in feedline 
tosses to an EME array^ on the 
other hand, would be a more seri- 
ous problem. 

Figure 3 will probably be ade- 
quate lor most readers, but for 
those of you who may wish to do 
some experimenting, here are (he 
general formulas for calculating 
the expected input SWR given the 
matched line loss and the SWR 
present at the toad, tt is a simple 
matter to incorporate these formu- 
las Into a BASIC computer pro- 
gram and arrive at answers tai- 
lored to your particular set of 
Circumstances: 

A = 10^(1/10) 

B = (SWRL - 1)/(SWRL + 1) 

SWRI - (A + B)/{A - B) 

where L is the matched-tme loss, 
SWRL is the SWR at the load and 
SWRI is the SWR at the input. 
More information on this topic can 
t>e found in the 15th edition of the 
ARRL Antenna Book 



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CIRCLE 151 ON READER SERVICE CARD 

73 Amateuf Radio * August, 1989 57 




NuiTtber 22 on your Feedback card 



mcuiTS 



Great Ideas From Our Readers 



Have a quick'n'easy circuit idea? Share it and get a one year 
subscription or extension to 73\ Clearly mark all entries as submts* 
sbns for Circuits to distinguish them from manuscripts. Send your 
entries to Circuits, 73 Magazine, Peterborough, NH 03458. 



INC 



MIC 






IPTT 20Kil 
— " ^w 

1/8 W 
AUDIO (IN) 



:x> 



2AT MEC 



=T> 



2JXT SPKR 



Figure 1. 



Coupfing Audio and 
PTT DC Circuits 

The August 1937 issue of 73 
contains an article by WB5WSV 
describing a way to Interface the 
tC-2ATwith the MFJ-1270 rNC-2 
Terminal Node Controller. Nor- 
rnaUy, a microphone jack in a 
transceiver provides 3-wire opera- 
tion of PTT and microphone audio 
where the circuits are kept sepa- 
rata. In the tCOti4 IC-2AT, howev- 
er, the circuits are combined and 
operated through a 2- wire mike in- 
put jack (center pin and ground). 
The circuit described in the 73 ar- 
tide exactly duplicates the micro- 
phone circuit. The relay does the 
PTT switch closure, and the 50k 
potentiometer replaces the micro^ 
phone element resistance. How- 
ever, the circuit Is too complex, 
relay-closure time delay is intro- 



duced, and the cost of the relay is 
an unnecessary expense. Also, 
there is the problem of providing 
-h 12V DC to operate the relay. 

For the last 15 months, I have 
been interfacing an MFJ-1270 
with an IC2ATby using a simple 
one-resistor circuit. I do not use 
the loudspeaker circuit. 

The reduced schematic, which 
is supplied in the 2i4rUser's Man- 
Ljal, show ; the PTT circuit as DC- 
coupfed to the jack, and the micro- 
phone input as AC-coupled. 
Figure 1 in WBSWSVs article 
shows the circuit of the hand-held 
2AT microphone. Notice that the 
microphone element and PTT 
switch are in series; closing the 
PTT switch provides a DC path 
through the microphone element. 
In voice operation, the audio sig- 
nal current is superimposed on 



TX AU&lO out 
PTT 

■ffx' AUDIO 
GROUND 



Ot-Q.\fj.- 



2 3K 

-JV^V — 



RADIO' 



TfP OF SfcfALL PLUO ihAtVlE PLUG J 
Hft+G NQT COhiNECTFn 



-* T<P OF LA ROE F^Lll^5■ (SPEAKS S J 



Figure 2. 



FT-727R/Data 
Controller Hook-up 

/ recently bought an f^FJ-1276 
controller to use with my Yaesu 
FT-727RHT. The MFJ-1273 man- 
ual gives a method for connecting 
an IC-02AT using a small (1:1) 
audio transformer, where the 
TNC RX audio and HT speaker 
are connected directly to each 
other. 

While this technique should 
work, it presents a problem from a 
convenience standpoint, since 
you need a separate box or enclo- 
sure for the audio transformer and 
leads. 

I called Yaesu tech support at 



(213) 404-4884 and got the follow- 
ing alternate hookup info for the 
FT'727R which avoids the use of 
a transformer. This should work 
for most other Yaesu HTs, and 
for many ICOM NTs which use a 
similar mike/PTT setup. (See Fig- 
ure 2 J 

The cap can be anything In the 
range of 0.01-0. IpF. The resistor 
should be Vz-Va watt. 

The cap and resistor can be 
wired up, then covered with heat 
sink material for a neat appear- 
ance. Tve tried this on my setup 
and it works greati 

Dale Gaudier N4REE 
Atlanta GA 



the DC PTT current. When inter- 
connecting to the TNC, the neces^ 
sary DC path is not provided 
through the audio (out) terminal: 
relay closure in the audio path 
does not make PTT current flow. 
R} (5Qkpot) is connected in paral- 
lel, from the audio (out) terminal to 
ground, to provide the DC path^ 
WB5WSV suggests 30k of parallel 
resistance for the DC path. I have 
used 20k and have had excellent 
results ^ 

Instead of having the series 
path for PTT and audio current 
run as shown in the hand-held mi- 
crophone, combine the circuits in 
parallel. (See Figure 1.) The TNC 
provides a ground path via the 
PTT terminal through the 20k par- 
allel resistor, and this resistor en 



ergizes the 2AT PTT circuit. Be- 
cause the MIC audio 1$ AC 
coupled, there is no interference 
with PTT operation. The audio 
generated in the TNC for trans- 
mission by the 2A T sees a parallel 
toad of2000O (audio circuit in the 
2AT), 20k (parallel resistor), and 
47k (PTT circuit in the 2Ar) with 
equivalent resistance of 1750Q. 
The TNC provides sufficient audio 
drive to handle this load. 

Connect receive audio in the 
normal manner. I would suggest a 
level control if you want to monitor 
the buzz. After an evening of 
packet QSOs, you will probably 
want to turn oft the sound and 
monitor with the blinking yellow 
light. Ian Kushner AF6K 

San Jose CA 




TO Z IWEI-ER 
tRA^JSCiFVER 



Packet/Voice 
Switch Box 

Have you joined the 
Packeteers? If you 
don't have a 2 meter 
transceiver dedicated 
to packet, would you 
still like to avoid the in- 
convenience of discon- 
necting the input to the 
TNC and reconnecting 
the microphone before 
you can use the trans- 
ceiver for voice? 

A simple switch box 
lets you enjoy the bene- 
fits of both packet and 
voice communications 
without the need to 
change connections. 
Figure 3 is a wiring dia- 
gram of the switch box. The con" 
nector for the microphone needs 
to be the same as on the 2 meter 
transceiver. I was able to find a 
cable with a plug on one end that 
matched the microphone connec- 
tor on my 2 meter transceiver. The 
connector for the cable to the 2 
meter transceiver can be any suit- 
able connector such as a DIN 
type, t used a D sub mate connec- 
tor (Radio Shack 276-1537) for the 
output to the TNC. The switcf] is a 
3-pole 2 position, either a rotary or 
push-push type. The audio input 
on this transceiver is from the ex- 
ternal speaker plug. I used a 
phono jack (Radio Shack 274- 
346) for this. 



.TO (MICROPHONE 
SiilME CONNECTOR A^ ON 
? VtETER TRAhfSC^IVei? 




Ay[>]D IN 



fel 



PTT 



MK 



PACKET our 

■ Z i 4 5 

•3 f 1 a- a 



ft? 



">1 

-a 



CHiiNiije PIN 
CONNECTIijNfS TO Fit 
YOUR PARTJCUL;AF 
SETUP 



PflC«:ET - IN 
MiCROPHOME-QUT 



Figure 3. 

I built my switch box with a 
fiange on one side and mounted it 
on the side of the TNC with one of 
the screws holding the cover on 
the TNC. The box doesn 7 shift or 
move when I change positions of 
the switch. 

fi4ostofthe newer high frequen- 
cy transceivers have an output on 
the rear for PTT.AFSK, and Au- 
dio, but this box Is useful for HF 
transceivers that don't fjave such 
an output and with which you have 
to use the microphone connector 
for the input to the TNC. 

No more inconvenient con nee- 
(Ion changesi 

Robert L. Dingle KA4LAU 

Dayton Ohio 



sa 73 Amateur Radio • August, 1989 



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CIRCLE 278 ON READER SERVICE CARD 

73 Amateur Radio • August. 1989 59 



Number 23 an your Feetfbaek card 



Rttyloop 



Marc L LQavey, M,D. WA3AJB 
6 Jenny Lane 
B^Uimore MD 27208 

One-Chip AFSK 

Generator 

Vou all are certainly a vocal 
crew. It may take me until Labor 
Day \o sift through all the respons- 
es to the First Annual Decade sur- 
vey published here- But, try I 
must, and I promise id let you all 
know the sense of the reader* 
Ship . . Just as soon as I figure out 
what it tsl! 

In I he meantime, here is the 
second in the series of one- 
evening kitchen table projects 
that you are all asking for This 
month, I have a one-chip AFSK 
generator. With its reasonable 
pyhty of emission, it should be 
useful for putting many of you 
onto RTTY. 

It's based on a versatile chip 
billed as a "function generator/' I 
picked up my last few on the bar- 
gain cfearance table at my local 
Radio Shack, While the XR-2206 
may not be in the latest Radio 
Shack catalog, l\ certainly re- 
mains available from ihem on or- 
der, or on the Jim Paks wall of 
many distributors, for about six 
buckSp list price. 

Figure 1 shows the schematic 
of the AFSK generator, which is 
easily assembled on a perf board 
fust by following the diagram. 
Take special note of the chip's 
+Vcc— it is ^10 volts DC. rather 
than the +5 volts DC common to 
other TTL chips. 

The RTTV keying input is basi- 
cally TTL level vollage, with a 
swing from less than one volt to 
more than two volts for the mark/ 
space transition. Most keying cir- 



Amateur Radio Teletype 

cuits should supply this level with- 
out much trouble. If you would like 
to key this circuit off of a 60 mA 
teleprinter loop, you will need 
some form of isolation, such as an 
optoisolator or reed relay. 

Meanwhile, the output frequen- 
cy of this device is as stable as the 
frequency determining compo- 
nents used, particularly the ca- 
pacitor connected between pins 5 
and6. Nominally a 0.01 pF capac- 
itor, this should be a high quality, 
stable capacitor, rather than the 
common disc variety. The latter 
has too wide a manufacturing tol- 
erance, and loo much drift in val- 
ue, to be used in this critical area. 

A high level signal on pin 9 gen- 
©rates an output frequency deter- 
mined by the combination of the 
capacitor between pins 5 and 6, 
and the resistor going to ground 
from pin 7. A low level signal on 
pin 9 similarly generates a signal 
dependent on the resistance of 
the potentiometer on pin 8. The 
formula is: 



f req = *.. 1 



RxC 

where (req is the output frequen- 
cy, R is the reslstarice presented 
lo either pin 7 or 8 to ground in 
ohms, and C is the capacitance in 
farads between pins 5 and 6. 

Wfth a 0.01 pF (0.D0OO0001 F) 
capacitor and a 45kO (45000 Q) 
reSFstor, a frequency of about 
2222 Hz would be generated. This 
is well within the common AFSK 
range. Therefore, the use of a 50k 
potentiometer allows frequencies 
as low as 2000 Hz to be gener- 
ated, with no real upper limit. If 
you like, for finer control, a 30k 
resistor in series with a 20k poten- 
tiometer would allow coverage 
of the 2000 Hz to 3000 Hz range, 



with much better accuracy. 

The perceptive among you may 
have noticed that I have not really 
labeled one or the other signals 
*'mark" or "space." That is be- 
cause such labels are, after all, 
relative. If you are keying this cir- 
cuit with a positive voltage for 
mark, and a zero or negative 
voltage for space, then the mark 
frequency will be determined by 
the resistor on pin 7, and the 
space frequency on pin 8, 

However, it you are using a 
computer lo key this circuit, 
and you are using the common 
RS-232 standard interface, then 
you may have a surprise coming. 
Mark voltage in the RS-232 stan- 
dard is a negative voltage; space 
is positive. This is just the reverse 
of what we were talking about. 
But. no problem. Just use the 
potentiometer on pin 8 to set up 
the mark frequency, and pin 7 for 
the space. 

You could pot in a reversing 
switch if it were important to you to 
swap mark and space frequen- 
cies. 

Now, for those of you who are 
VHF bound, the standard mark 
frequency is 2125 Hz, There are 
two standard shifts in use, the old 
850 Hz. so-called '^wide shift," 
and the newer 1 70 Hz. or '^narrow 
shift," To save you trouble with 
higher math, that yields a space 
frequency of 2975 Hz (2123 + 
850) \Qf wide shift, and 2290 Hz 
(2125 -I- 170) for narrow shift. 

VHF and SSB 

But these are for VHF AFSK, 
you see. If you will be feeding this 
AFSK into a single sideband 
transmitter to produce FSK, you 
don't need those frequencies at 
all. Most transmitters will not pass 
a signal upwards of 2000 Hz that 
well, as ihe audio stage is peaked 
for voice transmissions. There- 
fore, feel free to use a lower set of 
frequencies. There are two pre- 



cautions you should taka, though. 

First, choose a pair of frequen- 
cies, not harmonically related, 
that fits in the passband of your 
transmitter. If you are using wide 
shift, for example, don't choose 
850 Hz and 1 700 Hz. I know that 
they are 850 Hz apart, and rea- 
sonably low. but the higher is the 
first harmonic of the lower, Bad 
news! Better to choose 1000 Hz 
and 1SS0 Hz. or a similar combi- 
nation for a 1 70 Hz shift. 

Second, remember that FSK 
convention places the space on 
the lower frequency. That is, the 
frequency shifts downward from 
the mark frequency. When trans- 
mitting on lower sideband, the au- 
dio tone used for space Is the 
higher frequency, reversed from 
FSK convention. This goes along 
with AFSK practice, though, so 
there is some consistency. Once 
again, generate an AFSK pair with 
a low mark and high space, and 
use lower sideband to convert this 
into an FSK signal with high marfc 
and low space. 

Transmitting 

Now that youVe selected your 
transmit frequencies, you will 
want to couple the signal to your 
transmitter. The potentiometer on 
pin 3 controls the amplitude of the 
output signal According to the 
specs of the chip, about 60 mV of 
signat are available per kilohm of 
resistance, so a 50k resistance 
should generate about 3 volts 
peak to peak. 

The adventurous among you 
might chose to combine the previ- 
ous demodulator project and this 
monlh^s modulator into a box, 
with a common power supply, and 
make a small RTTY modem. Keep 
all that data flowing this way, to 
the above address, or electroni- 
cally, Either CompuServe {ppn 
75036,2501) or Delphi (user- 
name: MARCWA3AJR) are fine. 
Let's hear from you! 



tikiT 5.1k S.lk 



Wk 



AFSK Output 



-o 






I 



i -HliiF^ 



XH 
i 22BU 



-zmst 






Iry-7 

iiitjk y y 5t*k 
ill. 



^1- 



/t7 



1 uF 



TIL Uvel 



/77 



Figure 1. Simple one-chip AFSK generator. 
60 73 Amateur Radio • August, 19S9 



AFSK Generator Parts List 



Integrated Circuit 
Resistors 

{1/4 or Vz W) 
Potentiometer 

Capacitors 



Perf board 



XR-22G5 

5100O 
220a 

50000Q 

Miniature PC mount 

0.01 pF 

1.0 pF 

10.0 pF 



Jim-Paks or mail order 
RS 271-13305* $0.39 
RS27M3135 
RS 271-219 



$0,39 
$0.69 



RS 272-1 0652 $0.59 

RS 272-1434 $0.59 

RS 272-1436 S0.79 

RS 276*1 394 $1.99 



0.1 inch grid 

* Radio Shack parts are nearest whole values. Resistor values are 
nommaify within 10%, ForatI practical purposes, the available Radio 
Shack values are close enough for this project to the specified 
values. If you can get exact values, fine. If not, don't lose any sleep 
over it. 




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73 Amateur Radio • August, 1989 61 



Homing in 



Number 24 on your Feedback carcf 



Joe Moeti PE K&OV 
PO Box 2508 

Fullerton CA 92633 

S-Meters 

How well does your two meter 
FM transmitter hunting setup 
work when the signal is really 
weak? Getting an accurate bear- 
ing with a beam or quad is tricky 
when the signal just bafely breaks 
the squelch. Such situations are 
common at the beginning of 
hunts, particulaily after you leave 
the high elevation of the siarting 
point. 

Today's VHP and UHF rigs are 
very sensitive, but their S-meters 
are not. The S-meter takeoff point 
must be at an early stage in the IF 
chain to minimize saturation ef- 
fects and give maximum dynamic 
range (which is none too high any- 
way). So the typical S-meter 
doesn't start upscale until the sig- 
nal is about 10 dB above the 
Ihreshofd of detection. 

There have been a lot of hunts 
where fve gone well over halfway 
to the hidden T t^efore getting S* 
meter readings good enough to 
use for bearings. Without meter 
indications, the only way most 
hunters can get a bearing is to find 
the squelch break points and av- 
erage between them. This method 
is often inaccurate due to flutter 
and local noise conditions. 

The better equipped you are to 
get bearings on weak carriers, 
the better your chance of winning 
the hunt. Wouldn't it be great if 
there were a way to indicate the 
strength of signals that are too 
puny to move typical S-meters? 
There is! 

Squelch Secrets 

Ever notice that the squelch on 
your VHF-FM rig opens properly 

on stations that are too weak to 
read on the S-meter? That's be- 
cause the squelch senses the sig- 
nal level in the IF differently from 
the way that the S-meter does 
this. If the squelch worked Hke the 
S-meter. it would be very insensi- 
tive and unreliable. Instead, the 
squelch uses the "quieting" ef- 
fect that occurs on even the 
w^lkest FM or CW signats. 

Because of the very high gain of 
the IF stages in an FM receiver, 
the FM detector stage (the dis- 
criminator) outputs a high level of 
random noise when it's not re- 



ceiving a signal, sometimes as 
great or greater than the peak 

audio level of typical signals. Most 
of the noise is at high audio fre- 
quencies, well above the pass- 
band of the speaker amplifier. 
When any carrier-type signal 
(such as FM) comes in, even if it is 
very weak, this noise is quieted. 
The stronger the signaU the 
greater the quieting. 

Figure 1 shows the output 
slages of a typical FM receiver. 
Signal pickup for the squelch 
comes directly from the discrimi- 
nator and passes through an au* 
dio high-pass filter. The system 
senses the supei^onic noise com- 
ponents instead of the voice 
range audio^ then amplifies and 
rectifies the noise. Next, a logic 
circuit decides if there is enough 
quieting to represent a signal. If 
so, the squeich gate connects the 
discriminator audio through a tow- 
pass filter (the de-emphasis net- 
work) to the speaker amplifier. In 
many radios, the squelch control 
varies the gain of the noise ampN- 
fief , as in Figure 1 . In other sets, 
such as the Kenwood TR-7950, 
the squelch pot is part of the logic. 

WASDLO's Noise Meter 

Why not meter the squelch de- 
lector? Great ideal The rectified 
noise is a very sensitive indicator 



of the relative strength of feeble 
signals. 

There are two methods tor me- 
tering noise on ham VHF-FM 
transceivers The easiest way is to 
find a takeoff point in the receiver 
where there is a DC voltage pro- 
portional to the noise, then ampli- 
fy that voltage to drive a meter. 
That's what Vince Stagnaro 
WA6DLQ did with his TR-7950 

two meter rig, It's practical for oth- 
er rigs, too, 

WA6DLQ's meter box features 
a switch, S2 (see Figure 2) to 
make the unit either a noise meter 
or an external S-meter that tracks 
the one in the TR-7950. With this 
system, you hunt weak signals 
using the noise meter then, when 
the signal gets to near full quiet- 
ing, switch to the S-meter position 
and use your dashboard meter 
instead of the small one on the 
transcetver. 

The collec!or of transistor 012 
in the TR-7950 is an ideal noise 
meter ptckoff point. With no sig- 



nal, rectified noise turns 012 on 
hard, resulting in Q12 collector 
voJtage near zero. As the signal 
level rises toward full quieting, the 
drive to Q1 2 decreases until it is at 
cutoff, and the coilectof voltage 
rises !o atwul h-7.3 volts. The S- 
meter tapoft for the TR-7950 
comes from TP3. which varies 
from volts wilh no signal to +1 .6 
volts at full scale. 

The meter amplifier unit is basi- 
cally a straightforward DC gain 
stage using the National LM324 
quad op amp, U2. (See Figure 2.) 
This chip is ideal because it works 
when input voltage is near zero, 
with no need for a negative supply 
voltage. Be sure to strap and 
ground the unused sections, as 
shown. 

Easy-To-FInd Parts 

Most parts for this project are 
carried at Radio Shack, L1-L2 
and Ct-C4 are fillers to keep RF 
out of the radio and meter cir- 
cuitry, and can be omitted if there 



FM 
OETtCTOH 



DE 




EiurPHA5;is 







CQKtmOL 



9CJJ&DH 
CXWTRX 



RECTIFIEH 



Figure h Block diagram of a portion of a typical VHF-FM receiver, 
showing the discriminator, audio, and squeich. 



INPUT 



S' METER 

inptjt * 



4^0V 
* SOURCE 



NOfSf 

WET£R 

INl>Ut 




Ri4 
2.2 K 



e 



9V 



i 



S3 



U3 
LM39t4 



-T^^^' 
^^-6^- 




LEDt 



I FOn Tl*-^fA 



Figure 2. Schematic diagram of WAdDLQ's noise meter and externaf S-meter circuit for use with the Kenwood 
TR'7950and TM-621A transceivers. 



62 73 Amateur fRadio * August. 1989 



Continued on page SO 



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CIRCLE 252 ON Rf ADER SERVICE CARD 



73 Amateur Radio • August, 1969 63 



Hams A ts 



Number 25 Ofi your Feei&ack card 



Andy MacAliister WASZtB 
14714 KnightBway Drive 
Houston TX 77083 

HAMSATS 

AWAY FROM HOME 



Satellite mobile operations do 
well with tow-orbit amateur radio 
sateliites like RS-10ni and Fuji- 
OSCAR'12. The October and 
November 1987 columns dis- 
cussed mobile activity in detail. 
Bui what about portable setups? 

With gain antennas, the high* 
orbit birds, like AMSAT-OSCAR- 
10 and 13, can yield many enjoy- 
abte contacts while you're on 
vacation or at a weekend cam pout 
at the beach. Today many radios 
operate from 12 volts DC, and 
gain antennas don't need rota- 
tors; pointing adjustments are 
made only every 20 to 40 minutes 
during a typical satellite pass. 

Many VHP and UHF satellite- 
chasing antennas can be broken 
down into easily transportable 
pieces. If installed at a remote lo- 
cation, a pole just tall enough to 
keep the antennas above ground 
and aimed at the sky provides a 
sufficient mast. To rotate your an- 
tenna by hand, lash it to a gtx-foot 
stepladder for easy access. 

EquJpmerit Choices 

Your antennas for A-0-1 3 Mode 
6 [70 cm up and 2 meters down) 
slioutd be the best you can take 
along. For most stations the 
CushcraftAOP-1 package will suf- 
fice. Both the 20*element. 2 meter 
crossed yagi, and the 16~element, 



Amateur Radio Via Satellite 



70 cm antenna should be set for 
right-hand circutar polarization 
(RHCP). The 70 cm, crossed yagi 
construction project, featured In 
the May 1939 special satellite is- 
sue, would also do well. Keith 
WB5ZDP has been able to put 
these antennas together in only a 
few hours. 

Other antennas, like those 
shown in the photos Irom NBJJI, 
may draw both curious looks and 
great results. Alex uses a corner 
reflector fed with full-wave loops 
for 2 meters and 70 cm. The re* 
flector is made from two sheets of 
aluminum diamond screen 48 
inches by 20.5 inches, supported 
by a wooden frame. It uses PVC 
plumbing with a bearing lo accom- 
modate any polarization. 

The 70 cm loop is tuned to 435.5 
MHz, and spaced 8.75 inches 
from the 90-degree corner; the 2 
meter loop is spaced 1 8.25 inches 
from the corner. The assembly is 
placed on a surveyor's tripod and 
aimed manually at the satellite. 
Preamps for 2 meters and 70 cm 
are located at the loop feedpoints. 
Alex reports excellent contacts 
with Europeans while operating 
from his Long Beach, California, 
QTH. 



Field Day Operations 

During Field Day this year, our 
group in south Texas was active 
via Mode L {23 cm up and 70 cm 
down). We used an ICOM 1271A 
all-mode 1,2 GHz transceiver wfth 
a Down East Microwave 35 watt. 
solid state amplifier for the uplink. 
The antenna was a fouf-foot dish 



wfth the coffee-can feed system 
shown in TTie ARRL Handbook. 
The system, rotated by hand, was 
propped in place with a four-foot 
pipe in the ground and steadied 
by elastic cords. The winds occa- 
sionally get brisk on the beach at 
Galveston, so a few stakes and 
some rope helped. If you are con- 
sidering a portable Mode-L sta- 
tion, check WB5ZDP's dish article 
in the May issue of 73. This five- 
foot parabolic reflector provides 
excellent gain for good contacts 
with only 10 watts of 1,2 GHz 
energy. 

Our Reld Day Mode L downlink 
system incorpjorated a Cushcraft 
41 6T mounted near the dish. An 
Advanced Receiver Research 
GaAsFET preamp in front of a 
Vaesu FT780R mobile all-mode 
70 cm transceiver completed the 
operating position. All of the ra- 
dios ran from a group of batteries 
charged by solar panels* 

On your next portable outing 
you can discover the satisfaction 
of real VHF/UHF DX via satellite. 
With terrestrial line-ol-sight opera- 
tion, you have to cirmb a mountain 
just to get marginal copy from a 
nearby county or state. Give 
portable satellite activity a tryl 

New Publications 

AMSAT North America has an* 
nounced a new magazine and a 
completely updated beglnner*s 
guide with comprehensive details 
on A-0-13 operation from the 
ground up. 

The new quarterly magazine, 
the AMSAT'NA Journal, has Joe 
Kasser G3ZCZA/V3 at the helm. 
Joe was editor of the popular 
magazine Orbit in the early 80s, 
and in charge of the AMSAT 
NewsieUer during the late 70s. 
The new publication is available 



only to AMSAT members. They 
wilt continue between issues of 
the new journal, with timely ama- 
teur-satellite news items and orbit 
data. If you would like to join, dues 
are $30 per year Write AMSAT. 
PC Box 27, Washington DC 
20044, Of call the main office at 
(301) 589-6062. 

Keith Berglund WB5ZDP re* 
centty compiled a new Beginner*s 
Guide to A-0-13 operation via 
Modes B and J. Keith WB5ZDP 
compiled this fifty-page manual. 
The cost IS $7. For new members, 
it is $3. just enough to cover print- 
ing and postage. 

The guide contains companson 
Charts for commercial satellite an- 
tennas, 2 meter and 70 cm multi- 
mode rigs, receive converters, 
and preamps. Also included are 
discussions and explanations of 
computer tracking programs and 
printouts, instructions for the 
proper use of N connectors, data 
on coaxial cable attenuation, dia- 
grams of typical earth-station in- 
terconnections, and satellite 
transponder configurations and 
antennas. A complete uplink/ 
downlink frequency chart of AO 
13 explains its orbital characteris- 
tics and gives the beacon 
telemetry output schedute. The 
text, full of computer graphicSn 
was produced on a laser printer. 

The Amateur SateUite Report 
will certainly be an excellent refer- 
ence for all current and future 
satellite chasers. For the new en- 
thusiast, it contains a list of AM- 
SAT Area Coordinators with ad* 
dresses and phone numbers to 
provide local contacts for individu- 
al he)p> Copies are available at 
AMSAT booths during most ham 
conventions and directly from the 
AMSAT office. Get a copy. You'll 
be glad you did, 




Photo A. NdJJl's comer reflector with fuiUwsve loops for 2 meter and 70 
cm. &wH with a wood frame and mounted on a surveyor's transit, this 
simple satellite antenna has togged many DX contacts via A-0-13. 




Photo B. Front view ofNBJJt '$ comer refiector antenna. The antenna is 
tiltabte for any potarizatfon. 



64 73 Amateur Radio * August, 1989 



Ask kaboom 



Numtier 26 on your Feedl:>acl( canf 



Michael Geier K&WM 

7 Simpson Cauri 

S Buriington VT 05403 



14 



Schematic" Defined 



Most folks Vve met who claim to 
be diagram-literate point with 
pride to various components, 
thinking that the ability to recog- 
nize them constitutes *Yeadmg" 
the schematic. That's Jike saying 
that recognizing the letters of the 
alphabet is the same as reading a 
novel! 

The root ol the word **schemat- 
ic'* is "scheme/' and that is the 
diagram's purpose: to impart the 
scheme, or path of signal flow, of 
the circuit. 

Think of the components as the 
characters, the overall function 
(such as "transmitter'*) as the 
theme, and the signal flow 
through individual circuit stages 
as the plot winding its way through 
the various chapters. Like a book, 
a given circuit and Its diagram can 
involve many subplots and 
themes before arriving at its con- 
clusion, typically the antenna gr 
speaker of your radio. 

Good vs. Evil 

Also, like a book, there are good 
and bad circuits, and good and 
bad diagrams. Generally, late- 
model Japanese gear comes with 
good diagrams. Older stuff can be 
questionable. A truly great dia- 
gram will show voltages, and 
sometimes even oscilloscope 
waveforms for the inputs and out- 
puts of each stage. It may also 
illustrate signal flow with empha- 
sized or color-coded lines- Having 
this information makes Irou* 
bJeshooting a breeze, because 
you know what should be happen- 
ing when the thing works. The ser- 
vice manuals for most VCRs have 
this kind of data^ but it seems to be 
coming into use only recently for 
ham gear. 

A normal *'goDd" diagram will 
at least be logically laid out. with 
circuit stages arranged so that 
most signal flow occurs from left 
to right, and with clearly marked 
terminals, transistors, and iCs* 
(Some use actual part numbers, 
such as *'2N2222A/' while others 
may use a "callout" such as 
"Q11/' referring you to a sepa- 
rate parts list. Pari numbers com- 
plicate things less.) It you know 



The Tech Answer Man 

how to read it, it should quickly 
give you a sense of how the circutt 
^s meant to work, hopefully trig- 
gering ideas regarding where to 
look for trouble. 

A really rotten schematic may 
have sparse, or even no, compo- 
nent markings. It may be illegible, 
show layout of stages in a jumbled 
manner, omit parts, or even have 
errors. Fortunately, erroneous 
schematics are very much the ex- 
ception. 

Learning to Read 

Ok, you've got a repair job, and 

the schematic looks decent. 
Where to begin? In past columns, 
I've mentioned the idea that elec- 
tronic circuits are made up of bite- 
sized stages. If, for example, you 
examine the diagrams for various 
receivers, you*ll see that, while 
the actual circuitry can differ 
greatly, the basic scheme Is the 
same. There's an input stage to 
couple the signals from the anten- 
na, perhaps an RF amp. one or 
more local oscillators, some IF 
stages (easily identified by the 
transformers between each one), 
a detector, and an audio amp. 

Generally, at the center of each 
stage is an active devfce. Active 
devices are those which require 
power input from the power sup- 
ply, and modulate that power to 
achieve switching, amplification, 
or oscillation. They define the 
stage's purpose, and are often the 
cause of its failure. These devices 
include tubes, transistors, ICs (lin- 
ear and digital), SCRs. and most 
other semiconductors. 

Passive devices, such as resis- 
tors, capacitors, and corls, can be 
thought of as support systems for 
the active devices. The passives 
are the lungs and kidneys provid- 
ing the active brains with what 
they require to function, and most 
active devices are surrounded by 
them. 

Focus on the active device at 
the center of each stage, and the 
organization of the stages should 
become clear. To do this, you 
MUST have at least some idea 
how the active device works. If 
you don't know that current be- 
tween the base and emitter of a 
transistor makes the collector- 
emitter path conduct, then you 
can*t hope to understand the 
stage's function. There are many 
good books covering the common 



active devices, and I hope to ex- 
plore semiconductors in more de* 
tail in future columns. Let me em- 
phasize that you don't have to be 
an engineer, or need to under- 
stand complex formulas, in order 
to master this. If you comprehend 
Ohm's law, and have some basic 
knowledge of the active devices, 
you can Jeam to see the signal 
flow through nearly any circuit. 

Identity Crisis 

Probably the biggest hurdle tor 
beginners is the identification of 
stages. Which one is the power 
supply and which one is the audio 
amp? As a rule, look for a part you 
krK)w, and see where it's connect- 
ed. For example, once you find 
the speaker, you can't help but 
find the audio amp! Here's a guide 
to Identifying common stages: 

AC Power Supplies nearly al- 
ways have a transformer with the 
primary winding typically shown 
lo the left, and one or more secon- 
daries to the right. Hanging off the 
secondaries will be recttfiers 
(diodes) followed by big capaci- 
tors. The capacitors will be 
marked for polarity ( + or - , usual- 
ly + on the diagram, and - on the 
part itself). Sometimes, coils, tran- 
sistorSt and even ICs may be in- 
cluded. But the transformer is a 
dead giveaway. 

Audio Amps can be made of 
transistors or on a chip. Look tor 
the speaker and earphone jack. 
Discrete (non-chip) amps are usu- 
ally push-pull, which means they 
feed the speaker with two transis- 
tors working together, one for 
each half-cycle of the audio wave- 
form. The transistors are usually 
shown one above the other, with 
either the speaker or a capacitor 
leading to it, connected where the 
transistors meet. Once you've 
successfully recognized this type 
of stage, it'll stand out in your 
mind any time you see it again. 

RF ** Front Ends'' are the input 
stages coupling the antenna to 
the first mixer. They may be pas- 
sive or may contain an RF amp. 
Look for the antenna. In a 
transceiver, it may be coupled to 
both the transmitter's output 
stage and the front end at the 
same time. If the feed to the first 
active device is to its base or gate, 
then youVe found the receiver. If 
it's to an emitter or collector, 
that's most likely the transmitter 
final. There are some front ends 
using what is known as a "com* 
mon base'* amplifier, in which the 
base is grounded and the emitter 
or collector serves as the input, 
but it isn't common. 



Oscillator failure is a common 
cause of dead receivers and 
transmitters. In a transceiver, fail- 
ure of both together warrants a 
look at the oscillators. Look for 
crystals, variable capacitors, and 
coils. Generally, fixed-frequency 
and manually-tuned oscillators 
have connections for power, 
ground, and output, with no other 
inpyts^ Variable osci Haters used 
in synthesizers have an input lo 
control the frequency with a 
voltage. In these, look for varactor 
diodes, which look like a combina- 
tion diode and capacitor on the 
diagram. 

Mhiers and Product Detectors 
mix the incoming signal with an 
oscillator to heterodyne to a new 
frequency, or for audio deteciron. 
They can be active or passive. 
Passive ones look like the bridge 
rectifiers (four diodes in a dia- 
mond configuration) in power sup- 
plies. Active ones can be made 
from transistors or chips. Lock for 
two inputs, one from the preced- 
ing Signal stage, and one from an 
oscillator. 

tF (Intermediate Frequency) 
Amps amplify and filter the het- 
erodyned signals resulting from 
the action of the mixer. They al- 
ways have tuned circuits between 
them, usually using transformers, 
and there will be several in a row. 
In receiver, they are followed by 
detectors. In transmitters, you can 
follow them by driver amplifiers 
leading to the RF final. Either way, 
the succession of stages with their 
transformers (or sometimes ce- 
ramic resonators, which are 
drawn somewhat like crystals) be* 
tween them, makes them easy to 
spot. 

RF FrnaT Amps build up the 
power and pump it lo the antenna, 
in GW and FM rigs, they can be 
very simple, consisting of Httle 
more than a transistor with input 
and output transformers. In SSB 
rigs, they are somewhat more 
complicated, and can look simitar 
to push-pull audio amps, except 
that they have transformers at 
their outputs. In any event, their 
signals will lead to acorl/capacitor 
filter and then to the antenna or 
anter>na relay. 

Digital Controls are made up 
mostly of chips, which are drawn 
as boxes with lots of leads. They 
have many interconnections, and 
can t>e quite hard to follow. Usual- 
ly, your focus will be on their out- 
puts to the rest of the radio. The 
rows of chips are unmistakable, 

Next month — more letters. Til 
then, grab some schematics and 
start reading! 



73 Amateur Radio * August, 1989 65 



Numb^ 27 on your Feedback card 



Looking west 



Bin Pasternak WABITF 
28197 Robin A venue 
SaugusCA 91350 

Notable Ham-Corn Event 

At last!— the FCC released the 
newfy reorganized Part 97 Ama- 
teur Service Rules on Saturday, 
June 3, at the ARRL Oiamond Ju- 
bilee National Convention m Ar* 
llngton, Texas, Robert McNama- 
ra. Chief of the Special Services 
Division, and John B. Johnston 
W3BE. Chiel of the Personal Ra- 
dio Branch, brought the regulato- 
ry revision to the Arlington con- 
vention^ and presented them 
before a standing room only 
crowd. 

Part 97 Past 

Prior to this action, Part 97 had 
not undergone a major restructur- 
ing since 1951 when most com- 
munications systems in the Ser- 
vice were using HP hand-keyed 
telegraphy and AM telephony. 
Since then, a number of emerging 
technologies, such as SSB. FM 
telephony, VHP and UHF re- 
peaters, radio-teleprintiJig, satei- 
Irte transponders, digital commu- 
nications, television, and other 
modes have become popular. 
And, while rules have been modi- 
fied or added to accommodate 
these technologies, the result has 
been a patchwork quill of rules 
surrounding an antiquated and of- 
ten confusing structure. 

The New Part S7 

In a prepared press release, the 
Commission recognized that cur- 
rent amateur radio rules don't 
easily apply to modern amateur 
radio communications, such as 
packel radio. Thus* the FCC reor- 
ganized Part 97 of its rules to cre- 
ate a regulatory environment de- 
signed to encourage modern 
techniques and modern technolo- 
gy in the Amateur Radio Service. 
They also made the rules easier to 
understand, and deleted any un- 
necessary, obsolete, and redun- 
dant provisions. 

The essential tenets for the Ser- 
vice, however, remain the same. 
'The Amateur Radio Services 
consist of the Amateur, Amateur 
Satetlite, and Radio Amateur Civil 
Emergency Service (RACES)'* 
noted the FCC. continuing: "The 



amateur service exists for the 
purpose of seif training, intercom- 
munication, and technicaJ investi- 
gation carried out by duly autho- 
rized persons interested in 
amateur radio techniques solely 
for their personal purpose and 
without any pecuniary interest/* 

Part 97 has now been restruc- 
tured into a format of six subparts 
and two appendices. These are: 
•Subpart A: General Provisions, 
which contains those rules con- 
cerned with license and station lo- 
cation requirements, 
•Subpart B: Station Operating 
Standards, which comprises 
those standards that apply to all 
types of amateur station oper- 
ation. 

•Subpart 0: Special Operations, 
which contains the requirements 
that apply (o non-standard opera- 
tions such as repeaters, beacons, 
and the Amateur Satellite Service, 
•Subpart 0: Technical Standards 
for ali operations. 
•Subpart E; Emergency Commu* 
nications, which contains all rufes 
applicable lo operating in distress 
and disaster situations along with 
the rules governing RACES* 
•Subpart F: Quatifytng Examina- 
tion Systems, which is self-ex- 
planatory. 

•Appendix ) lists the geographic 
area of the world where the FCC 
holds jurisdiction of the amateur 
service. 

•Appendix W lists Volunteer Ex- 
aminer Coordinator regions. 

More Liberal 

The new rules combine those 
regulations that pertain to an ama- 
teur station providing emergency 
communications with those that 
govern RACES stations. They do 
not, however, change the basic 
principles or purpose of the Ama- 
teur Service in the United States, 
Also unchanged is the "Quiet 
Hours Rule" that can be used to 
impose restrictions as necessary 
on the operation of amateur ser- 
vice stations to eliminate interfer* 
ence to home entertainment 
equipment. The proposed change 
to delegate blanket authority to 
impose quiet hours was a major 
source of irhtation lo the amateur 
community, which feared that 
FCC engineers might abuse such 
a power. In the fmal version of the 
revised Part 07, the authority to 



impose Quiet Hours will remain as 
it has been. 

The general prohibitions a- 
gainst amateur stations transmit- 
ting communications as an alter- 
native to other authorized radio 
services, such as commercial ra- 
dio services, has been clarified. 
They now allow any required 
emergency communications. The 
new rules also penmil the use of 
amateur radio stations to provide 
communications that retate to the 
public's safe observation and par- 
ticipation In parades, ma rat ho ns^ 
and similar public events so long 
as the principal beneficiary of the 
communtcations Is the public, and 
any benefit to the event sponsor is 
incidental 

Communications relating to the 
buying and selling of amateur sta- 
tion apparatus— such as ham-ra- 
dio swap-nets — wilt also be per- 
mitted as an exception to the 
prohibition against business com- 
munications. However, the new 
rules expressly forbid any com- 
munications by persons seeking 
to profit from such sales or pur- 
chases on a regular basis, e.g. on- 
the-air dealers. 

Another exception i n this area is 
business communications that as- 
sists journalists in filing stories. 
Such reports, however, must not 
detract from the efforts of other 
stations that are actually engaged 
in providing emergency communi- 
cations. Just about every mass 
media outlet in the nation, includ- 
ing ABC, NBC, CBS, and CNN, 
lobbied hard for this exemption. 

With respect to operator license 
examinations, the FCC codified 
the policy thai a telegraphy receiv- 
ing test alone is adequate proof of 
tx}th sending and receiving abili- 
ty. The exam lest message must 
be sent for at least five minutes 
and contain all tetters, numbers, 
and prosigns. Also specified is the 
exact number of questions thai 
must be answered correctly for 
each exam element to replace the 
previous method dealing with per- 
centage of correct answers. The 
new rules also give administering 
Volunteer Examiners !he authori- 
ty to require expert verification 
that an examinee with a physical 
disability requires a reader or tran- 
scriber other then the one admin- 
istering the exam etement. In an- 
other rule change, the concept of 
the Regional VEC was deleted 
and all VECs are now National 
and permitted to service tests 
wherever they desire. 

The new rules retain the '*defi- 
nitions" sections, and some terms 
used in the Amateur Service 



Rules have been shortened and/ 
or simplified. By way of example, 
the terms ^'beacon/* "repeater," 
•*earlh station," and '"space 
station" are now defined. The 
Commission also included an ex- 
ception lo the prohibition on inter- 
national third party communica- 
tions that states the prohibition 
does not apply to any third party 
who Is eligible to be control opera- 
tor of the station. 

An exception to the time limita- 
tion for a RACES Drill has been 
incorporated where an Emergen- 
cy Planning Official has approved 
the drill or test. Also, the "Good 
Amateur Practice" requirement 
has been combined with the rules 
governing frequency selection, 
frequency sharing, and malicious 
interference. Also under the new 
rules, a representative of a foreign 
government is not barred from 
holding a reciprocal permit. 

With respect to repeaters and 
allied relay operations, the re- 
vised rules delete the antiquated 
requirement that relay operations 
be discontinued within five sec- 
onds after cessation of the relayed 
radio communication by the user 
stations. The restriction that a re- 
peater cannot transmit on more 
then one channel from the same 
location was also deleted. 

In addition, the FCC also clari- 
fied the permissible emission 
types to be used by amateur sta- 
tions, and codified or clarified 
many other policies concerning 
amateurs that have evolved over 
the years as interpretations of ex- 
isting rules. Also codified Is the 
existing FCC policy concerning 
state and local regulations gov- 
erning the height and placement 
of amateur station antenna struc- 
tures. The new Part 97 also in- 
cludes the essential holding of the 
Commission's PRB-1 limited pre- 
emption ruling that local regula- 
tion of an amateur service anten- 
na structure must not preclude 
amateur service communications. 

The Future 

The new Part 97 is definitely a 
step fonA^ard in modernization of 
the United States Amateur Ser- 
vice. Thanks to the work of Per- 
sonal Radio Branch Chief John B. 
Johnston W3BE and his Staffs our 
service has a new lease on life — 
one to carry it forth into the 21st 
century and maybe, hopefully, be- 
yond. 



(Adapted from FCC News Re- 
lease— May 30 1989 with special 
thanks to Joe Schroeder W9JUV 
and Fred Maia W5YI) 



66 73 Amateur Radio • August, 1989 



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•Tlw CofTunodw^e Ham's Compaiiion 
160|ppBolu%eliil mfin-maiian cTCi Kk?cTift|: a 
rr for die ham jjadt. wliric fafind ipeoat- 
Eied prognniii, the CoaBBodotE-pacrtet 
connecUflD. and wor^\ $9-9S 

•Maiter Handbook of 1 001 
C Ire uitft— So Hd- State Edition 

by Kenddil Webster Sessions 
With thj4^ ottuianding reference in hand, 
ekctronics hohb^isi^ pnd profe^siiHitih 
wJH never have m search fur schcirunj^js 
again. Completely updated, the book ii* 
thorough ty Indciicd i^nd all UXil cincuitu 
alt clearly itlUMnati^J, 4:!0pa§^cs. 

tl9.95«o(lciivfr 



bjJimGmUis^El 




•World Praaa Services F^reqyefide* 

(RTTY) frf Thomas Hamnpoa WWVfV 

A contpr?Ner»iv^e manual cowcrinf RadiiMefetype nevh^i morcitor- 
uig^cofitaui^ dl informuiofl— artKeniu. Kveiv^n^ lennioa] units. 
piwi dme oaamkifc frequency Itiu. Coven 65 World Pisa Ser- 
vioea broadcaidng 10 Ei^I^. "The Orifiisal ft^m Boift." 84 
pa^ic&. av.T? 



•ftftdki KafKlbOoli. 23nl Editton IIIMj /. Orr irti54i 

(Hard cover only n This book is. lilted wiih 840 ptgtt GS e^-erydijn^ 
you «-ani(?d in knj74 abcnt r^io cnmmuiiicatkin, Yoy will giH an in 
depth tiudy of AC/DC fundaincnUiU. SSB. antcrmasi, ampiifkm. 
pqwef lupphc* und mofc. S29*95 

* Bas tc AC CIrc U Ita by ^kattity R, Futton/Jakn Raw/ini 

A slcp by Mcp approach for the be^inninp ssudenl technician or 

engineer Ci>vcf^l concepts, icTtr.ii and iiijiihernLLiic.ti required So un 
dcj-btand AC circuil problems in nn cuiiy ?!i retui iLfrini;]:!. $24.95 

•Eaay-up Antennas for Radio Lltteners and Hamfl 

Ay Edwm^ M. Sott 
Would you like to learn how 10 emtiitrucT Inw-co^l^ casy-ia-cr^x 
ameoma? Eaay-Up Anieiinas wtll b:lp you do jti.'a thai. SIIL9S 

•Forrest Ulmms' Circuit Scrapttooit II 

Jfy ForrfW ^i- Himmi, HI 
Frvfn dK ankles in thnbDO^yoD will leaifl ho Wi- to iofoniiaii^ 
will tsoMe you to eiprfimei« with MQSFET, tmkog and 
drctnti, la&o dkides and opto ekcin^iki! f 19,15. 



Additions Irom the ARRL 

Library of Fine Books 



•FCC Rtfle Book 

The FCC Rate B^tok U invatwable a* a iludy guide ior liae iuy;ulu,- 

tory materiai fuund t»n thn' c*ijuri;^ and as a handy rcferGiu:c &S.1I0 

«ARRL Data Book 

Thiit handy ncFerenee n i vihiride ud fo ehe RF design er^neer. 
icchnician, radio ■mjUcui'. and cxpcrriinenier Cocnmotiiy mtd 
ublcSi^ charts, ami ihoMr hBrd'to-remenribeT farmuln are found in 
iMim^iourr^ SJ2.M 

*lriiederence Han<ibooh 

Thts 250-{Mgc ^ X "ii L^ lAniieo from an RFf desith^i pen p ec five 

aial u, adi&ry of his ciperwiKeb in ^vii^ iB&cffereace pff t i hicB >i- 

iiJJi 

•AHRL 1339 Handbook 

TIk llOO^page itMy-M»|h edition «»Hiaim o%tt 3J00 U^ic%, 
iigurEf, and clmrtx. The Handbook ts paarked with component dam 
and coosinicttorr anitks. S2I.06 



*Solld S:ate Design 

StpHd Siatt Dtisign i*^ thrnsk luil of good, basic inforrnannn— cir- 
cuit ddst^ns Eind their appliculions. and descriptiiiJisiuf receivers, 
tranjim Liters, power «upp!ie>i«<id tcsi^tjuipment. SO.OO 

*ARRL Antenna Boolt 

The ARRL Antenna Binjk rcprcaenlji the best and rnoii hi^ly 
fcpided ioformaliun on anteiina ruiidamentid» traAHnbakift 
Itnem. ficsign and cott^lruction of wtne amennM. S I S^Ott 

■ARRL Operating Manual 

The ARRL Operaliai Mmal ia piackcd »ith inftmHtida tm how 
to make the ben me of your ilalton, tncludiap tmcffacing htime 
com^lfr^. OSCAR, VmVH¥.eomee6M^ SU.M 



•T»c)iniciari/Geii«f»l Oaftt License Manyal %5,d& 
« Advanced dais Lie en»# Manual 18.00 
•Extra ClaAs License Nianiial SK.oo 

BegtBniQf Vk ith Tuiie in the 'A'lorld wiih Hanti^dio for die Novice 
and pTtifTiK&mg thniu^h the cntif al]y acdaiaied ARRL Liceruic 
Manual senes for die Technician tbroagh Extra Ojuk; you will 
Hnd paiJiing each exam elemeiti a Knap! There are nccuratc tci^l 
c^plBnaEion^ of ihe matiiTiHl covered ak>ng wilh FCC i^eHtion 
pcMis and answer keys. 



•Vagf Antenna Design 

Ham Radio puhluilwd ;ii s-tjries of articles on Yugb. The mareriitl 
fr\>in ihcyc artH^'k^ thai it prcMi'nted here WHa pnliihcd nttd en- 
panded by Dr L4WM>n $15^00 

•Hovice Amenna f^Mbook 

NotykEs will \wTn* amofig odier titinf:ii. ham itngwa*. nperalc 
md whu fuverna their cfleciiteneaa Ibr filun' sad bag-diiuiicc 
Cdmmimkaiiaii. fS.Ofli 

•ARM. RapMltr 0«rtKtary tdes-isio 

Thi4 <e&km tfr H% laipv and iKtedct o«er4T5 beaconi coicr- 
tns fieqiiCKie^ ffun 14 litiiL 10 24 GHl. Ytm'U alio titid a/v& 
13 jcn regular repeafier Ufiii^aDdoverlJOOc^ipcaten. iS.oo 



•SaFtellite Anthology 

You'll find the laicsii inlniTnuiii^n on QSCAR:^ *^ dirv D w wcl^ as 
die RS ^itrlltic^ InfiiriniiiioFi on the use of di|tilal rnndesi, tnirk- 
hip. anirnniis, RL'DAK. mitfncoinpuieT and niord %5,^ 

•Low Band DXing 

This book uhnws. yciu how (0 ireet the chaJk+n^en i>f tSw diiTcrcnt 
fontiij of 160^ SO and 40 meter propagation! wiih cfldi-tiive tinter^ 
nas. equipment and operating ^itfatL-gies. SlO.OO 

*5atetllte EKpefimeAt«rs Handbook 
Uodcr one cover n *hat the AmaleiiT Radio * r needj^ to 

know in onleir 10 CHnmumcate through I3bs OSCAR ^iaidhtca. 

StOJt 

•Votir GaiwmY to Packet R«d«o 

Fiikd wittt tnfornuthMi tot ail amalear^, thu tknok lells every- 
Ma^ yoQ need to kmm abOM ibir populif new itk^ bow to wa 
aarteiL qpi proc m ytm need and more- SlA^Ot 

•Tufw In the World wtlh Ham radio Ktt 
Titae 10 tfic ^orld with Ham radio ha:& put t^K tun biL% into 
lezmmf vfhat Anuieitr Radio ii a^J abtAiL AIao iiKli*ded it itvo 
C-90 rape ccii^iiCh , One lape teaches die code, tte other pr iiv ides 
practice, $1S.1M) 

Tune in the World— Book only $U.OO 



UNCLE WAYNE^S 
CODE TAPES 

nis course mak£S ihw code s& incredibly 
simple ia learn that only the total ignorance 
of it is driving the no-code farwiics. Almost 
anyone can pass the Novice code test with 
less than three haurs of practice. If you start 
right you It zip through your General test in 
just a few hours. Genesis starts you rights at 
IJ-perfor each character, so you only have 
to learn ihe code once. This is the fasiesi 
code svstem known to man. Or woman. 



I.J'* * p. 



$5.95 



5 H pen Till* A [he bcpnoiiig tape ^ lakii^ you timxigji &k 
26 trncn, 10 moiihef^ uid neccuaiy puncouiioo^ tom- 
plctc with practice €v&y «iep of die way Tie ease of 
learning give^ conlidcncf even to ihc faint of htan. 



riu' SlkklL^- 



$5,95 



6 + trpm-ThLJi a the practice tape for iIio^kc who iiurvivcd 
the S wpm tBpu, and ix'& &\^ the I ape rt>r the hfoviee and 
Technician licien^s. It l» comprised of one solid hotir of 
code, ChaTacier<i are sent 4it I :^ wpm and spaced at 5 wpin. 
Code groups arc entirrly random charai^Mcrst scat in groups 
of five— definneiy n^jcmcmoruabk"! 



Buck Kroakcr 



9' J' ■ 7^' 



ij 4- iA pm-Code fimps a^in, m a bmk 1 3 + wpm so 
you'll be ftaUy ai e^e wii^ii you »it down in: front of a 
stoety-eyed voiuntoa^ eumiJier wtko flKtu scndii^ yqv 
pLaui lanfTuagc ai otdy 13 per. You'll need iha extra 
margin to o^crromctlv sheer panic uni^crul in nwist le%t 
tttuatwfn You've come dm far. %o don't get cixk dqr 
tkow^ 



t'i>tinii:t'cjijs ' 



SS.9S 



20+ wpm^cmffifulatkoia! Okay . rhc chaltcnge of code 
i% wfut'i gonen ytm thi^ far. ^ don't quii tnm Go for the 
Eiira clahsi license We s^nd the ^ode fiMcr than 20 per. Ii's 
J ike wear inn lead weights on your feel when yaa mn; you'll 
wonder ¥iihy the examiner i^t^^ndin^ M)«lowly! 



IINCLE WAYNrS BOOHSHELF 



•Ftret Book of Modem Electrcin^ Fun Prnfects 

Edttrd by Alt SMAtfg 
LoetJcinf i*m a wvt to I^vc fim, int^wcme yiwr le^hntoU e^^prrtise. 
Bid nave rmme^'— ddl di tbc sune lume? Thi^ uniqiK ccmpcDdnum 
cbeck'fuJl of pfiifccts wiir show yoa btw, 11 9,95 

*Cornmodore &4 Traubl^e^hoollng 4k Repair Gultic 

by Mobrrt C. Bttmntr 
TTiiH book will guide you step ty step tlirfxigh ihu comptexiiies nf 
making iimj^k repairs lo yotir ConimfxioK 64. $I9.9S 

•C 64^1 28 Programs for Amateur 

Rudio & E lee t ron Ics by Joseph / Vmr 

The electtDfiicN hobb^^isi, pTu^rainiiJcr, engineer and icchnicion wit I 
^}oy ihr t;i^k nricntcd pro-grdm&i fur amatC'ur radia and clBctrumci^ 

•Fun Way Into Electron ics kj Did TmH 

Thti. 3 vt^umc icnc^ fi^iuro miniductipry pfOfccts Tor bcguiikii^ 

dc!ciioni€%. cRlliiSfSSl<&- W.95«*- 

• Vot 1 tngluNi» 30 pfiqjecU on bmk miierid^i mad Uw4&, ccmipQcieni 

diMTTipcioWtfld i pndi? iDiHcveBliiit prDjccb. 

*Vat 2 ftvd 30 fsrojccts covering inpKi vae^ ■» ielderinf OAkj 

eiitwt bijftnb. 'Ut^ii^ rrultimai^s mbA reading ciicidi dagTMrn^, 

*¥cA 3 ^somn advanced pfofcfu immcigating intcfraicd riroiiiJi, 

coastractXB^ FC boanb uid buikltaf a min synd^rsuicr. 

•fias Ic Elecirfcfly/ETeclron ics i>^ Ao^/f R. Mm riile 

Ji] ihtiN tNi.st^ electric it vclcctrunics i(cric$ uf te^iboql^ a mucb:rn 

pni^rurnnu'd fcNrrrul \s used lo pn^if^lil l^ matcnal In a logical jjimJ 

ca.'ty Ei^UEhlcr%turKJ way, 51 1 .95 eai 

*Vol I infrudkicfrs i he student lo ihe basK cf}ricepi*( (if circuit Tunda- 

wcmahr 

•Vol 2 fHow AC/DC CitcuLts Work) This vututnc feuilds on tbc 

bj^ich. I[ pvcn detailed infurniulion [Ui serici:^ and parallel eireuit^; 

crretl>^ im imJucEdiice, capadlance and rrumlnrmer ajction. 

•Soltd-State Projects You Can BulM 

byfiudolfF.Gntf/Gmf^J. Whtdra 
Have ymi wianhed for challenging tfinnvittivc prnjccts. irna^tna 
lively 4ki4gnni and &kiliru]l> Jrbuit^cd ii.} Mimuljiif your wm^ <;w- 
tiivp tlijnkiiiy? If fo^ dM& book w-is wniten iix you! SIQ.95 

•The 55S Timet Ap|»lit>ations 
Sourcebook with Experlmenta ^ Hvwm^M^ MmUm 

Thii bomk i> JitMnii ihc 555 timer li * t1| %how y«i bow tp i^c it by 
lucj f and w iih otlicr lotid sui&r dcv Kes . ^.9$ 

•Weather Satelllle Itandbook tf Dr. §t^k E. Taggen 

Dr Tji^^jn hus wrilleii this book {o !tcr^ e l:KMhei.perieiicedanuieiJr 
sHellile cnibuL>i«i,*ri and the new comcf Amolcur wicaiher ^aicJIiEt; 
activity r^fM^ienis a uniqur bJeml uf intercuts enciMnpas^ing clec - 
mmici. mclcrtili;^ and aatEonaiftici. ft 6.45 

•On* Evening Eled^ni&s Pro|ecla 

byCaittn ft. Graf and Richanf S. GiiS» 
16 prnJC'Ciji ihnt can be a,ssemblcd in a jtimplc home workshop, a 
vnltugL' detector. solid-Mutr lelephunc bcl1„ ii irnntiisloraudtu ampli- 
fier, liHd U vlhen, This i^ anea.sj' tn und^^i'^ltii'id, cnjovsbk guide to 
L-umpJetiflg biwk clectrpoics pjiojctu - wiil)>iisi one evening's wort . 

•The Baaic GuWe lo VHF/UHF 

Ham R ad (o frr F^mtrd M. Soli 

*thtAtMktL pfi>vt<ie£anr^T3icriiitTicidiiCtic)4i!Olifeonthe 2.6aDiJ 1.25 
maef tttfki% ah vidl as 23. 33. and 70CM (6.95 

•Crsah Course in Electron ies Technoiogy 

bj Lfuis E. Fttmzfi^ Jr. 
With J prr»ycn Tornw of prDframmnf imtructioeu ilis bookfcachc* 
yim the ha^Ki-v uf cl«incii> jnd cki:iit}iiK:i^ ui a &ep^^9Bp^ easy- 
Iv-ynJcnOAnd fashioo. 121.95 

•Sho4littcv« Radio Lisientng with the Experts 

inr Gerry t. Dexi^r 
Du ym lit fur kmg hours in frorvt ofa rodki reLiei ver li&tcniiig lo faint 
sounds and nois^ii? Then you^m a SWL'isr df DX'cr. and yuy can 
probably u«c iiotmc help. ^2.95 



•Mastering Packet Radio: The Handft^n Guide 

hy Davf ingmm K4TWJ 
Pocket fUdicf IN [tie holtc^t^ muiil rapiJIy expanding area of anmleur 
eonuuurtiiAiMim Wrttlen for the eiitluicuf enlliui»iasit. nwstering 
]hu.'|u!L RiidMi will put you on the t;yum|! edj^ uf this dtgital cununu- 
nieationE nrvjilut inn £12.45^ 




AMATEUR 
RADIO 



ATTN: Uncle Wayne 
Forest Road 
Hancock, NH 03449 



• AdC^S of D&CfWMliM by Eati Jatob WMers 
Wntten for snyonc wmnttn^ m learn ihe basics of dectnncs. this ita 
ctirnprchrofi^, wttt illustiaAcd kaxk al lie fiiialnnLiairi of eiee- 
triHiK^s and dectnxiic appJicaiiofai. 113.95 

• AJI AbfHil Cubkfll Qtiad Animnas 

h Waiuim Orr W6SAIf Utaan Csyftm W21JL 
The ^^Cl^aMk'" oci QuJHi ikisij^n^ theory, cooAnKtion* dperalicici. 
New feed and maiching liyalcni^ New dala. $9.9S 

• Kram Anteniw HJandbiH^k 

by Wmiam Orr W6SAI/SluaFi Cowan W2lX 
Ydgi beam theory. comLruyiiopi. operation. Wire heam*i, SWR 
tnirvci. N4ii[ching<j:xsk-iii'>. A "miLat" Tor !icriou!»DXcf?i. $11.95 

*T1k Radio Amateur \nieniia J land book 

by WUiiam Orr W6SAI/Sttmft Cowm W2iJ[ 
Ckar. compteftr Al] abtjut wire ■nleniia.s. beanssi. tuncr%, bsUum^. 
cvmx. tw&afei, SWR and KfUhrn. Bcsi }Dcatk)i]&^ afUriina htrtglM- 

$nss 

•SifBfilr, Ljfnfe-CiHt Wife VnleniuG^ fnr Radio Amatmni 

by H*//«iw Ott W6SAJ Stuart C&wan »1LX 
All New! Low-cost, muHi-haAJ antennas . inexpenstvc beanH. "In- 
vajiibk'" antennas for hana in ^'lough" locatkns! New dala SI I ^95 



•AA Almui V crtkal Antcnnxs 

by WUImm Orr WS^AlSimmrt Cowtm W2LX 

Eflecttve^ low-coat verticals 10^160 m. -DX« multibaftd^ caa^aci 
verticals for junall ipmxi: ffoung;[e£ eqinp.; bgbieinnf . SIO*^ 

•All About V H F Araalnir Radio by WOtiam Orr WSSAI 

DX propitiation, VHF Yap and Qyutd beaiius, repcaiCTS ami hovv 
eJkv work> OSCAR juitellitef and how to use them . SI I -WS 



THE WORLD 

$4.ao 



V**' 






.J ^-^, 



Yes. places you*ve never even heard of! 
Nearly 400 DX countries e leaned from Ihe 
Awards List of dozens oflARU tncmbers— 
tnore countries than any other map avaiEable 
anywheref ARRL'&DXCC map doesn't even 
come close! 



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Uncle Wayne's Bookshelf Order 

□ The Packet Radio Handbnak ......... 

D The Beginner'^ Handfxiok 

n DX Power: Effective Techniqiies 

n Trans miner Hunting: Radio Direction . 
D The Digital Novice 

□ The Commodore Ham*s Companion . . . 

D Master Handt>c¥^k of 100 1 Circuits 

n World Press Servicer 

DRTTYToday ., 

O Shortwave Clandeitiiie Confide ntia! 

D Shortwave Director> . . . . , , ,^ 

D The Hiddeii SJgmiis on SaieHite TV , . . , 

C GGTE Morse Tutor floppy disk , , , 

D Radio Handbook ...... .,*>.,.* 

D Basic AC Circtiits , « ^ « * . . ^ i. . « , , 

D Easy-Up Antenna.^ .....,.,..». 

D First Book orMtxlern Hlectronics 

D Commodore 64 Troubleiihooting 

n C64/ 12S Programs For Amateur Radio . 

D Fun Way Into Elect ron icii Vol. 1 

D Fun Way Into Electronics Vol. 3 ...... 

D Basic Eltjctricity & Electronics - Vol. I . 
D Ba^ic Elecfriciiy & ELeetronJcs - Vol. 2 . 
P Solid State Projects You Can Build .... 

D S55 Timer Applications Sourcebook . . . 
D Forest Mims' Circuit Scrapbook U . , • , 

D Crash Coorsc in Elect nankrs 

D Shortwave Radio Listen ing with , 

G Mastering Packet Radio 
D ABC's of Ekcimmcs ,,.*.. 
n Magic of Ham Radio _ . — 
D I9g9 Passport to Worid Band 
D Genesis Code Tape 



« d ■■■ H ■# 



Form 

. $ 14.95 D Stickier Code Tape ....... 

. $ 1 6.9S n Back Breaker Code Tape 

. % 1 0.00 n CourageouK Code Tape ....... 

$17.95 D DX World Map , 

. S 9.95 □ Weather Satellite Handbook 

. 5 9.95 D One Evening Electronics Projects 

.$19.95 D The Basic Guide to VHBtJHF ,. 

.$ g.95 DWorld Ham Nei Dir. ........... 

.S 8.W OFCC Rule Book 

.S 8.95 DARRL Data Book , . . - 

*SJ7.95 D Interference HamSbook 

. $19.95 DARRL 1989 Handbtxik 

,S20.00 DSolid Stale Design 

. S29.95 n ARRL Antenna Book .,,,..•... 

.^4,95 DARRL Operating Manual 

. $16.95 DTechniciani'Gcneral Class ....... 

$12.95 DAdvanceCbjis 

$19.95 DExtraClasii 

$14.95 nVagt Antenna Design 

$ 9.95 G Nov ice Antenna Notebook ...,,. 

$ 9.95 G ARRL Repeater Directory .-.-.. 

$! 1 .95 GSaielilte Anthology 

$11.95 GLowBamlDXing 

$10.95 G Satellite Expcrtmeniers 

$9.95 GGatcway to Packet Radio 

$19.95 GTune in ihc World Kii 

$21 .95 CTunc m (Ixxik only) 

$22.95 CCubkaJ Quad Antenna ,,,,., 

S 12.95 GBeam Antenna Handbook 

S12.95 C Radio Amateur Antenna .. 

$ 3.95 G Low-cosi Wire Antenna ..,., 

$14.95 □ VertkaJ Antennas .......... 

$ 5.95 DVHF Amateur Radio 



p ^ « t' 



« ■■ v « 



. .$ 5.95 
, . $ 5.95 
, .$ 5.95 
.$ 4.00 
,.$16.95 

..% 6.95 
. $ 9.95 
.S 5.00 
.St2.00 

,$12,00 
.131,00 
.$12.00 
.$18.00 
*$i5,00 
.$ 5.00 
.$ 5.00 

*$ %.m 

.$15.00 
.$ 8.00 
.5 5.00 
.$ 5.00 
.510.00 
.$10.00 
.$10.00 
.$15.00 
.$12.00 
$ 9.95 
,$IL95 
.111.95 
.$11.95 
. $10.95 
-$11.95 



You may order by mail, telephone, fax or our Bulletin Board, All payments are to be in US 
^nds. Please add $2.50 for shippin g and handling for all orders, AUow 3 weeks for 
delivery. 



Name 



Street 



City 



State 



Zip 



TOTAL $ 



Card# 



Expiration Dale 



Telephone: (603) 525^201, FAX: (603) 525-4423, Bulletin Board (603) 525-4438 
Mail: 7J Magai'mc , Attn. Uncle Wayne, Forest Road, Hancock, NH 03449 



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DAE DMC DVtSA □Check.^ionev Order ■ 

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Number 2d on four Feedback card 



We IV PROD UCTS 

Compiled by Linda Reneau 







PRODUCT OF THE MONTH 

AZIMUTH COMMUNICATIONS CORPORATION 
THE AZIMUTH AWARDS QSL LIBRARY 

Azimuth announces Its Awards QSL Library afbums for organTz- 
ing and protecting your QSL cards. You can select an album for 
each kind of award— DX Century Club, Worked All Zones. Worked 
All States, and Worked All Continents, with beautiful graphics for 
each award. Or you can order an album lor all your QSLs in general 

Each album js made of durable, quality vinyl. Us 20 scralch-resjs- 
tant pages holding t20 cards. Each pocket page holds six 4 x 6 
cards. 

The introductory price is $20; extra 20-page packs are $13. Add 
$2.50 for shipping and handling per album and page pack (forefgn 
orders, add $7.50 US]. California residents please add sates tax. 

If you order now. Azimuth will send you FREE their AWARDS- 
BASE Log & Tracking Program for IBM-PCs and ctones. Retail, this 
program costs $25, For VISA and MC orders. caM (800} 882-7388, 
or wnte Azimuth Awards QSL Ubrary. Depl> E73, 1 1845 W. Olympic 
BL, Suite 1100, Lo$ Angeles CA 90064. Or circle Reader Service 
Number 201, 






ADVANCED ELECTRONICS APPLICATIONS, INC, 



Advanced Electronics has a 
new antenna tuner. The AT-30Q 
features a low-pass design to re- 
duce or eliminate TVI; coverage of 
3.5-30 MHz; 300 walls continu- 
ous power: a dual-needle watt- 
meter; and two 18-tap inductors 
for tuning accuracy. The meter 
range selects 300 watts and 30 
watts lo ease tuning. 

Front panel controls include im- 
pedance adjustment, and switch- 
ing for power, antenna, and meter 
lamp. 

Rear panel connections include 



a coax connector for input, two 
coax connectors to antennas, one 
coax connector to a dummy load, 
two ceramic feed-through con- 
nectors 10 balanced faedlines, 
one for stngle-wire antennas, and 
a DC power connector to the me- 
ter lamp. Pnce, $250. Advanced 
Electrontc Appiicaiions, inc., PO 
Box C2160. Btdg. O & P. 2006- 
i96th SW, Lynnwood WA 9803&- 
091$. (20$) 775-7373, Tetex: 
6972496 ABA [NIL UW. FAX: 
(20$) 775^2340. Or circle Reader 
Service Number 202. 




KENWOOD USA 
CORPORATION 

Kenwood*s new dual-band TH- 
75A has many of the features of 
the dual-band mobile transceiver, 
and uses the same accessories as 
the TH-25AT (except for the soft 
cases). 

The dual watch function allows 
you to monitor tx)th bands at the 



same time~ For readibility, it has a 
large muHt-function LCD display. 
Ten memory channels for each 
bartd store frequencies, CTCSS. 
repeater offset, step information, 
and selectable full duplex opera- 
tkin. Two memories are for odd 
split operation. 

The CTCSS encode/decode 
is buitt-in, and the automatic 
band change switches bet- 
ween main and subband when 
a signal is present. The TH-75A 
also has auto offset selection on 
2 meters, four-way scan, tone 
albert system, and battery-saver 
circuit. 

Extended receiver range cov- 
ers 140-163.995 and 438- 
449.995 MHz; transmit on ama* 
teyr band only. The TH-75A is 
modifiable for MARS and CAP, 
with permtts. 

The TH-75A operates on 1.5 
watts on 2 meters and 70 cm, and 
5 watts when it operates on ^Z 
volts DC (or PB-S battery pack). A 
filhium battery backs up mem- 
ories. 

Suggested retail price. $550. 
Soft case optional, Kenwood USA 
Corporation. Communications & 
Test Equipment Group, 2201 E. 
Donimguez Street, Long Beach 
CA 908t0, (213) 039-^200. 



DOPPLER SYSTEMS, INC. 

Doppfer Systems has expand* 
ed its RDF systems to cover 
frequencies up to 1 GHz. The 
5000 series, using a remote RF 
summing circuit, is accurate 
±5 degrees. Doppler offers a 
wide range of antennas to cover 
frequencies between 108 and 
1000 MHz, 

With a narrowband FM receiv- 
er, the system works in a quasi- 
Doppler mode. Using a patented 
technique, four antennas ar- 
ranged in a square pattern simu- 
late a single, rotating antenna. As 
it moves toward the RF source, 
the apparent frequency increas- 
es, and as it moves away, the ap- 
parent frequency decreases. A 
narrowband FM re- 
ceiver detects this 
Doppler shift and 
sounds a 300 Hz tone. 
The RDF system 
measures the phase 
angle and displays 
the bearing. Quasi- 
Doppler mode is good 
for tracking unmodu- 
lated carriers and 
standard NBFM sig- 
nals. In amplitude 
mode with an AM re- 



ceiver, Ft's good for tracking air- 
craft band amplitude modulated 
signals, including ELTs, 

A typical installation consists of 
a processor/display unit, an RF 
summer unit^ and one or more an- 
tennas. A receiver is required. 
You may use a good quality scan- 
ner, but if you use transceivers, 
service monitors, or spectrum an- 
aly2ers, take care not to transmit 
through the direction finder. 

The price of an RDF Doppler 
System ranges from $955 to 
$1650. depending on the type of 
installation— mobile or fixed— 
and antenna requirements for 
your operating frequencies. 
Dopphr Systems, tnc, PO Box 
31819, Phoenix AZ 85046. Or cir- 
cle Reader Service Number 206, 




06 3 



^£E1 



70 7$ Amateur Radio • August, 1989 



ELECTRONIC 
SPECIALISTS, INC, 

Electronic Specialists has 
eKpanded Iheir patented isofator 
line to include remote power 
switchmg. power fail interrupt, 
and 20 amp options. Suppressor 
performance of all units has 
been expanded to 39,000 Surge 
Amps for added equipment 
protection. Isolators, with wide 
band-high attenuation channel 
filters, are widely used in industri- 
al and laboratory computer or 
sensitive equipment applications 
to provide smooth AC power con- 
ditioning. 

Available in Commercial, Indus- 




trial, and Laboratory Grades. 
Prices start at $100. Electronic 
Specialists. Inc., 171 South Main 
Street, Nattck MA OtlSO. (800) 
225-487$. Or circle Reader 
Service Number 203. 




THE RADIO WORKS 

The CAROLINA WINDOM/2© 
is a half-size 40-10 meter version 
of the CAROLINA WINDOM© 
with performance equal to the lat- 
ter. It covers seven HF bands, in- 
cluding all WARC bands. A trans^ 
match is required on all bands. It 
is fed with 50O coax^ 

It has a 10-foot vertical radiator 
section which works w^th the 66- 
fool long horizontal radiator to 
produce complex radiation pat- 
terns. Simultaneously, the hori- 
zontat radiator acts as a counter- 



poise for the vertical radiator. 
Radiation takes place high in the 

air for high efficiency, since 
ground losses are avoided. 

Each antenna comes assem- 
bled, complete with matching 
unit, vertical radiator section, 
highpower transmission Line Iso- 
lator®, #14 stranded antenna 
wire, glass-filled insulators, 
CoaxSeat* and illustrated manu- 
al. Price, $70. The Radio Works, 
Box 6159, Portsmouth VA 23703. 
(804) 484-0140.0T circle Reader 
Service fsiumber 204. 




ELENCO ELECTRONICS, INC. 

Ihe Elenco SG-9000 is a high 
frequency signal generator capa^ 
ble of AM modulation. It incorpo- 
rntfis a stable RF oscillator with 
frequency range of 100 kHz to 
t50 MHz. It has an easy-to-read 
dial. Frequencies of 455 kHz, 4.5 
IVlHz, and 10.7 f^ Hz are specially 



noted for easy setting. 

An internal audto frequen- 
cy of 1 kHz is available for 
AM Of external use. External 
crystals may be used to lock 
the oscillator to, say, a fre- 
quency between 1-15 MHz. 
The RF output voltage is 
variable and has a 20 dB 
attenuator switch. The SG- 
9000 comes with instruction man- 
ual with circuit description, bk>ck 
diagram, and schematic. Cost, 
$196. Eienco Efectronics, 150 W. 
Carpenter Avenue, Wteeling IL 
60090. (312) 54 1 -3800. FAX: 
(312) 5^)^0085. Tetex: 706061 
ELENCO UD. Or circle Reader 
Service Number 207. 



HEIL SOUND 

The HM-tO microphone is a! the 

center of Heil Sound's Concept 
2000. Unlike other amateur radio 
microphones, the HM-10 uses 
professional cannon-type 3-pin 
connectors. You can buy the HM- 
10 by Itsetf, or with the Hell HC-4 
'*DX Dream Machine" or the Heil 
HC-5 full range element. 

Interface the HM-10 to your 
transmitter input connector by 
specifying the cable with the fight 
color: red, Kenwood; yellow. Yae- 
su: blue, (COM; and black, spe- 
cial. Operate ptt or vox, hand- 
held or desk mounted. Adjustai>le 
booms and goose-neck mounts 
available. 

The HM-10, buift for durability, 
is heavy and rugged. Wired, with 
plugs, carrying case, stand 
adapter, colored cable, and foam 




windscreen, the price is $80. Neil 
Sound, PO Box 26, Madssa IL 
62257. (BIB) 295^3000. Contact: 
Bob Heil. Or circle Reader Service 
Number 205. 




HUSTLER, INC. 

Hustler announces a new HF 
mobile mast for their line of mobile 
resonators and accessories. Mod- 
el MO-4, a 22' all-stamless steeJ 
mast, creates many mounting op- 
tions previoysly unavaifatile to the 



mobile HF operator. It's ideally 
suited for RVs, trucks, vans^ and 
cars with plastic bumpers. You 
can mount it on trunk lips, mirrors, 
roof racks^ and ladders. In con- 
junction with standard Hustler 
resonators, you can install the 
MO-4 on a high quality magnetic 
mount. 

You can make a shortened 
dipole with two MO-4 masts arrd a 
matching pair of resonators. You 
can assemble a tri-band dipole, 
good for apartments and areas of 
restricted space, by adding two 
Hustler VP-1 triband adapters and 
two resonators. 

The MO-4 comes with three 30" 
tip rods for 10, 15, and 20 meter 
resonators. No tip rods are neces* 
sary on 40, 75. or 80 meters. Sug- 
gested retail price, $20. Hustler, 
fnc, One Newtronics Place, Min- 
eral Wells TX 76067. (817) 325^ 
1366. Or circle Reader Service 
Number 209- 



MFJ ENTERPRISES, INC. 

Dave Ingram K4TWJ shows you 
how to collect, restore, and oper- 
ate classic ham gear in his book, 
Golden Classics of Yesteryear, 
published by MFJ Enterprises, 
inc. Remember the 6L6 rigs, 
Heathkit DX-100, Collins KWM-1, 
WRL Globe Scout, HaJiicrafters, 
RME, Hammulard, National 
HROs, EJmac tubes, Vibroplex, 
Speed-X. Dow KEY, McElroy. . .? 

The book is packed with reaMife 
tafes and easy-to-build weekend 
projects from the 20s. 30s, and 50s. 
K4TWJ shows you how to build a 
"Tailender'^^n early DX memory 
keyerthat requires no power sup- 
ply or electronic parts, but works 
"like a champ." He includes fa- 




vorite cIrcuitSt telegraph keys and 
bugs, and other ham topics. 

Dave has authored over 300 
articles and 12 books. He writes 
the "World of Ideas'* column in 
CO^ Order his latest book for $1 
from MFJ Enterprises, Inc., PO 
Box 494, Mississippi State MS 
39762. Telephone: (601) 323- 
5869 or (800) 647-1800. FAX: 
(601) 323-6551. Telex: 53 4590 
MFJ STKV. Or circle Reader Ser- 
vice Number 210. 



73 Amateur Radio * August, 1989 71 




Nufntwr 29 on your Feedbwck card 



Mike Bryce WB8VGE 
2225 Mayftower NW 
MBssifhn OH 44646 

Portable Operation 

operating portable mqyires 
very little — one poitabfe radio and 
a source of powBf to operate it 
from. IVe always been inclined lo 
operate portable with solar pan- 
^s, but sometimes they Ve just too 
much trouble to set up. Likewise 
for conventional 110 volt power 
supplies. Ruins all the fun if you 
have to dtg op a hundred-foot ex- 
tension cord. Operating portable 
from tlie deck of the house iust 
isn't the same as doing the same 
in a field or in the woods. 

Because of the small current 
drain of most QRP rigs, battery 
power is quite attractive. A smaU 
Gel/Cell" will operate my Arg- 
onaut for many a weekend. But 



Low Power Operation 

what do you do when that battery 
needs charging? I just connect it 
up to the solar panels and let the 
home-brew control circuit do its 
thing. What's this? You donH 
have solar paneis for battery 
recharging? Well, lhat*s what 
we're going to build this month: a 
110 volt battery charger, but with a 
twist — actually, a pulse or two. 
This unit will charge all kinds of 
batteries, from Gei/Oells lo sealed 
lead-acid batteries, vented lead- 
acid batteries, and good 'ol 
NiCds. 

Tve tried to do something a bit 
different this month. With a few 
exceptions, you can get all the 
parts from the local Radio Shack 
store. I built my version from both 
the junk box and Radio Shack. 
But before we get loo carried 
away, tet's look at how this critter 
works. 




Photo A. The compfete charger. Note the 0-500 mA panel for aurrem 
adjust 





Photo C. Large capacitor IF fitter for the 1 10 volt supply. 



Battery Charging Methods 

You can charge batteries by 
several means. Two of the most 
popular are voltage limrting and 
curreni limiting. Current limiting, 
as the name implies* limits the 
current going into the battery. The 
voltage is allowed to move about, 
but within limits. As the battery be- 
comes charged, the current drops 
and the voltage comes to rest at 
the full charge voltage of the 
battery. 

In voltage limiting, the voltage is 
preset at the full charge setting, 
and the current Is aJkiwed to move 
about. If a really discharged bat- 
tery is connected to a constant 
voltage charger, heavy current 
will flow into the battery and possi- 
bly damage it. 

As with alt battery chargers and 
the batteries being charged, the 
manufacturer has the final say as 
to how much current and at what 
voltage the battery will be consid- 
ered "chafged." I've been using 
Yuasa sealed lead-acid batteries 
for portable use. They are rated ai 



20 hours at &} mA to 10,5 volts 
(1.2 amp/hour). Great for running 
HW-8s in the woods. Yuasa rec- 
ommends, for cycle use» a charge 
voHage of 1 4 .4 to 1 5 volts, with the 
current at 250 mA. 

Universal Battery Charger 

So« enter the universal battery 
charger. It's nothing special; in 
fact, you've probably seen some 
of the circuitry before. Most of it is 
tried and true, sure*to-work stuff* 
Now. that's what we lx>th like to 
hear, right? 

A \o{ Of battery chargers use the 
LM317 to control the charge 
voltage. Since I'm not one to re-in- 
vent the wheel, Tm going to use it. 
too. The LM317 comes in many 
case styles. Radio Shack sells the 
LM317 in the popular TO'220 
case. If you have one in the T03 
case, so much the better. The 
TO-3 case seems to dissipate 
heal better, A trimmer in the ad- 
lust lead of the LM317 sets the 
output voltage, f^tice there are 
two different trimmers. I ackted a 
switch to select between two 




Photo 8. trtside view of the charger. Most pans mount on the perfboard. Photo D, Hear sink on LM31 7. Bridge rectifier is gtued to the back paneL 
72 73 Amateur Radio * August, 1989 



different set pomts. one for 12 volt 
charging and the other for 6 volt 
charging. Now for the added 
goodies that make thts charger a 
bit different 

Notice that a 2N2222 transis- 
tor's collector is connected to the 
common of the selector switch. 
When the transistor ts off, the reg- 
ulator operates normally. When 
the transistor is on, it ptiils the ADJ 
line to ground, through the 220Q 
resistor. This turns the LM317 off. 
Now you're asking, "What turns 
the transistor on?" Good ques- 
tion. Simple answer, A 555 timer 
chip, that's what. The 'ol come-to- 
the-rescue 55& is wired for stable 
operation. With the components 
shown, we can adjust the duty cy- 
cle of the 555. The more OFF the 
transisior is, the more current will 
flow into the battery via the LM317. 
Less duty cycte, less current. 

Advantages Of Pulse Charging 

In other words, we charge the 
battery by using high current puls- 
es, rather than a constant cuneot. 
Those 7.2 volt RC batteries are 
charged just like this. That's why 
you can recharge one 72. volt bat- 
tery from a car banery in less than 
15 minutes. Charge currents can 
approach seven amps or more, 
but the duty cycle is low enough to 
avoid damage to the cells. 

By using pulse charging, wa 
can charge the battery without 
overheating it. The parts passing 
the current to the battery will also 
operate cooler. All and all, it's a 
slick way of charging a battery. 

Let's look a bit closer. The tim- 
ing components adjust the duty 
cycle of the 555. Tve pan el* mount* 
ed the adjustable control so that I 
can adjust the current to suit dif- 
ferent capacity batteries, with the 
same voltage. The output of the 
555 IS a square wave. The more 
on, the higher the duty cycle. You 
can look at the output with a scope 
or a VOM. However^ you'lf only see 
a voltage move about (as you ad- 
just the duty control) on the VOM 
due to the meter averaging out the 
result, The scope will reveal a 
square wave. Not the best looking 
waves you've ever seen, but 
square waves nonetheless, which 
will turn on the transistor switch. 

Time to heat up the soldering iron! 

Construction Details 

As noted earlier, you can buy 
most of the parts at Radio Shack. 
The meter f used in my charger, 
which has a range of 0-500 mA, 
came from my junk box. I found it 
the most useful when setting the 
charge rate for the batteries. 



140 V 






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Schematic for the universaf battery charger. 



Most of the circuit is like a circuit 
for a conventional power supply. 
T1 supplies 1 6 volts AC at 2 amps, 
A bridge rectifier, rated at 4 amps, 
supplies DC to the filter capacitor. 
I used a small glob of epoxy to 
mount the bridge rectifier to the 
back case panel. The filter capaci- 
tor, a computer grade unit, 
smooths out the DC. Don't worry 
too much if you can't get the same 
amount of capacitance I used, just 
tiy to get it as large as possible. 

A 7612 regulator supplies 12 
volts to the 555 timer, since the 
direct output of the fitter capacitor 
is a bit high for the timer. 

The LM317 requires a heat 
sink. \ use a small screw-on unit. If 
you wishp use the inside back case 
to heat-sink the regulator. If you 
do, be sure to insulate the device 
from the metal chassis. 

1 mounted the parts, including 
the trimmer pots, on a Radio 
Shack copper>plated perfboard. A 
socket for the 555 makes trou- 
bleshooting easier. In point-to- 
point wiring, keep the heavy cur- 
rent leads short and direct. Attach 
wire to the battery with five-way 
binding posts, tf you follow the 
schematic, you'll have r>o trouble 
building the charger. 

Check over your wiring, espe- 
cialty the 1 f vofi wiring, for er- 
rors. You might want to divide the 
charger into smaller modules for 
building and testing. Good idea. 
Start wfth the 110 volt side. You 
should see about ^ volts on the 
filter capacitor, 

With the 555 timer out of its 
socket, turn on the supply and 
check for 12 volts on the output of 
the 7312. While the 555 is stilt out 
of the socket, switch the voltage 
selector switch to either 6 or 12 
volts. Adjust the proper trimmer to 
the finish charge voltage. Switch 
to the second trimmer and adjust 
it also. Again, I set mine tor 7.2 
voKs for 6 volt batteries and 14.4 



volts for 1 2 volt batteries. 

Turn off the unit and Install the 
555 timer into the socket. With a 
tmttery connected to the output, 
and the voltage switch set for the 
proper voltage, adjusting the duty 
control should make the current 
meter go up and down. Of course, 
if the battery is fully charged to 
t>egfn with, you won't see much 
current flowing. Because of the 
blocking diode in series with the 
output, you can reave 4he baftery 
connected to the charger and not 
worry about the battery discharg- 
ing if the charger is turned off. 

That's about all there is to it. 



One final point. This unit is only for 
charging batteries. DON'T try run- 
ning anything from it. You'll get ail 
kinds of strange results. 

Wtth a few changes, you can 
have a really versatile unit. By 
using an LM350, output currents 
of 6 amps are possible. If you build 
the charger as 1 did. you can 
charge up to 1.5 amps. I don't 
recommend this charger to 
charge large lead- acid batteries, 
1 05 amp hours or more. 

Next time you get the urge to 
operate out in the field, you won't 
have to worry about dead bat- 
teries! 



AMATEUR TELEVISION 



SURVIVES 100,000 FT. FALL 

KPA5 1 WATT ATV XMTR ON 434 MHZ WORKED 
PERFECTLY IN WB8ELK LIVE CAMERA BALLOON 
THROUGH 100.000 FT AND BACK TO CONTINUE 
RUNNING EVEN AFTER FREE FALL IMPACT IN THE 
MOJAVE DESERT! VIDEO SEEN FOR 300 MILES. 








C/K/FOfiNM 



KPA5-E board $169 
Shouldn't your ATV transmitter be as reliable? Weather 
you want to put one In a balloon, R/C mode!. Robot, use 
as portable ATV xmtr, or gel one in our ready to go 
TX70-1 for the shack, with P.O. Electronics you seethe 
best! Compeinlon receiving downcon verier board TVC- 
2G $49, or ready to go in a cabinet - TVC-4G $89. 



TX70-1 

XMTR 

$259 




TVC-4G 

RECV 

CONV. 

S89 

THE ATV TWINS 
Hams, Call or Write for our latest catalog of ATV gear! 
Transmitters sold only toTech or higher licensed amateurs 
varified in latest Callbook or copy of new license. 5/89 



(818) 447-4565 m-f eam-5:30pm psl. 

P.C. ELECTRONICS 

2522 Paxson Ln Arcadia CA 9100e 



Visa, MasterCard 

Tom (W60RGJ 
Maryann (WQ6YSS} 




Number 30 on your Feedback card 



FECIAL EVENTS 

Ham Doings Around the World 



tisfmgs are free of charge as space 
permits Ptease sen<i us your Speaat 
E¥ent two months in advance ofttw 
issue you want it to appear in. For 
exampie. if you want it to appear m tfm 
June issue, we should receive it by 
March 3t. Provkie a ctear, concise 
summary of the essentia} detaifs about 
your Speciat Event. 

JACKSONVILLE FL 
AUG 5-6 

The 1969 Greater Jackson viUe Ama- 
teur Radio & Computer Show will be 
downtown at the Prime Osbom Con- 
vention Center. Huge air-conditioned 
indoor swap area, exhibitor's section, 
forums, programs, FCC exams, prizes, 
boat-anchor auction. Registration, $5. 
Swap area tables, S15 for the week* 
end, $12 Saturday only, $6 Sunday on- 
ly. Exhibilors contaci Btfjy Wittiams 
N4UF St (904) 765^230 Of (904) 766- 
2410^ PO Box 9673. Jackscftviffe FL 
3220S. Fof tables, registration, inlo^* 
mation, (Include SASE}, contact 
Giwamf Jacksonvifie Hamfesi Associa- 
tion, PO Bom t0623, Jacksonwtfe FL 
32207,(904)360-9193, 

MtLDORD CT 
AUG 5^ 

The Greater Bridgeport Amateur Ra- 
dio Club will hold its special event from 
Booth Memorial Park al the City-wide 
Picnic on the 5th, and from ttie Shake- 
speare Theater grounds on the 6th. 
There will be dancing, actors, singers, 
bands . Club call WAl RJ I on 20 meters. 
Contaci f^Ame. 1 1 Pearl HUi St., Mitford 
CT 06460. (203)874-8740, 

CEDAR RAPIDS I A 
AUG 5-6 

The Cedar Vailey Amateur Radio 
Clyfa, Inc., is sponsoring Iheir 'Sum- 
merfest 89" at the air-conditioned 
Teamsters Halt. There will be amateur 
radio seminars. FCC exams^ a lafge 
variety of cofnmercial vendors, a large 
flea market, and free outside tailgatrng. 
One hiotel* several motels, and mail 
nearby Talknn on 16/76 and 52. 8-foo1 
tables, $6. Commefciat, $15 first table, 
StO each thereafter. Admission, $4; 
age 12 and under, free. Summerfest 
69, Ciiff Ootcf sherry, 2926 Shaffer 
Drive SW. Cedar Rapids tA 52404. 
(3W}356-S849, 

RANDOLPH OH 
AUG 6 

The Porlage Amateur Radio Cfub, 
Inc., ARRL affiliated, will sponsor ^ts 
4th annual Hamfair at the County Fair- 
grounds. Tickets, $3 In advance, $4 at 
gate. Children under 12 free. Indoor 
labies, $8 each. Flea market spaces. 
S3 each. Activities include forums and 
nonham activities. Computer hobby- 
ists welcome. Mobile check^n on 
T 45. 390 (negative offset), Joanne So- 



tek KJ^^. Portage Amateur Radio 
Club, inc., 9971 DiagonatRd, hAantua 
OH 44255. (2 f 6} 274^^240. 

A14GOLA IN 
AUG 6 

The Steuben County Radio Ama- 
teurs present the 29th Annual P.M. Pic- 
nic and Hamfest at Crooked Lake. 
Prizes, picnic BBQ chicken, inside ta^ 
bles for exhibitors and vendors, 
overnight camping. (County Park 
charges fee.) Communications on 
146,62 and 1 47.81 /.21. Admission, $3. 
Bonn W. Laird W89Yir, Steuben 
County Radio Amateurs, %Laketand 
Electronic Supply, 202 W. Pieasant 
St., Box 330, Angola IN 46703^ 

LANCASTER PA 

AUG 6 

The Red Rose Ref^eater Association 
is sponsoring its Computer-Fest at the 
McCaskey High School. Features: 
Computer hardware/software, tail9at- 
in9. prizes, inside, air-conditioned. 
Talk-in on t47.0l5/:6l5- Admission, 
$4. Children under 14 free with paying 
adult. Computer Fest Committee. PO 
Box 5092. L^/Kaster PA t7B0t. Verv- 
dors contaci Jim Unviiie, PO Box 5029. 
Lancaster PA 17601 or Fred Hammer- 
sand Tet. (717}569-U77. 

BERRYVILLE VA 

AUG6 

The 39th Annual Winchester Ham- 
fest, sponsored by the Shenandoah 
Valley ARC, will be at the Clarke Coun-^ 
ty Rurltan Fairgrounds, Admission $5, 
before July 15» $4. Children under 12 
and no n ham spouses free. Tailgate rs 
and limited tables, $7. Commercial ex- 
hibitors. Donations from major manu- 
facturers. VE exams. Talk-in on 
146.22/.e2 and 146.52 simplex. Joan- 
ne Btaker WB2ChdV, (703) 869-^*378. 
Or, SVARC. PO Box 139. Wincfiester 
VA2260f. 

GREENFIELD IN 
AUG 6 

The Greenfield Amateuf Repeater 
Association Hamfest wiU be ai the 4H 
Fairgrounds. Admission, S5: chikfren 
under 12 free. Flea market. 8- fool 
table, $5. Commercial Bldg. S7. Talk 
gate, $2. Talk-in frequencies 
147.000+ or 444.725 + . Keith Dafrym- 
pie N9GWK 2210 Wayne Or, Green- 
field IN 46t 40. 

RHINELANDER Wl 
AUG 12 

The IDth annual Rhinelander 
Swapfest, sponsored by the 
Rhinelander Repeater Association, Ihe 
North erwoods ARC, and the Toma- 
hawk Repeater Association, wilt be at 
the ice Arena. VEC testing, free park- 
ing, dealers welcome. Admission, $1; 



tables, $5 each prepaid by July 31; 
bring your own tables, S3 per space; 
outside tailgating, no charge. 
Rhinelander Repeater 146.34/. 94, 
Tomahawk Repeater 144.83/145-43. 
t-eonard Bauman K9RMN, 804 Lincoin 
Street, Rhinelander Wf 54501. (715) 
369-3296/5564. 

WSSEX JUHCTtON VT 
AUG 12 

The Surfington ARC will hold its arh 
nual hamfest at tfie Champlain Valley 
Fa tf grounds- Admission. $4 (Canadi- 
an, $5). Children under 12 free. Camp- 
ing available. Talk-in on 146.34/ .94. 
Barb Kimbali N1DLE, T Sundown 
Drive, Witfiston VT 05495. (802) 878- 
5555. 

FAIRMOUNT1N 
AUG 13 

The Grant County ARC will hofd its 
annual swapfest at the Fair mount Play 
Acres Park. No ticket, no charge, bring 
lunch* table, chairs. Talk^in on 146.19/ 
,79, Dennis Cievenger KA9JUB. 516 S. 
Walnut FairmounI IN 46928. (317) 
948-935h 

WARRINGTON PA 
AUG 13 

The Mid- Atlantic ABC hamfesi will 
be at the Bucks County Route 611 
Drive-Ln Tfiealre. Tailgaiing spaces, $2 
each. Admission. $3, Talk-in on 
147 06/R and 146.52/S, AI Masfin 
W3DZh (215) 446-4936. Or write 
MARC, PO Box 352. Villanova PA 
19085. 

ST, CLOUD UN 
AUG 13 

The St. Cloud Amateur Radio Club 
Hamfest will be held at Whitney Senior 
Center. Tickets, S3; additional tickets, 
$2. Prizes, talk-in on 34/94 primary, 
616/016 secondary. Scare, Box 141, 
SL Chad MN 56302. 

GEORGETOWN KY 
AUG 13 

The Central Kentucky ARRL Ham- 
fest. sponsored by the Biuegrass Ama* 
teur Radio Society, Inc., wfll be at ihe 
Soott County High Scliool. Techntcal 
forums, license examinations, awards, 
and commercial exhibFts in air-condi- 
tk>ned facilities. Outside flea market 
space free with admission. Tn^kets $5 
m advance, $6 at gate. Talk-in on 
146. 16/, 76 repealer. Bill DeVore 
N4DfT, 112 Brigadoon Parkway, Lex- 
ington KY 40503. 

VALPARAISO, IN 
AUG 13 

The Porter County Amateur Radio 
Club presents the Annual Northwest 
Indiana Hamfest and Computer Fair at 
the County Fairgrounds and Expo Cen- 
ter Features: Walk-in VE testing, large 
flea market, and many commercial 
vendors. Talk-In on 146,776/. 175 or 
146.52. Admission, $4 at the gale, 
$3.50 m advance. Kids under 12 free. 
Hamfest Committee, PC ARC. PO Box 
1782, Valparaiso IN 463S4. 



BRIDQEWATER NJ 
AUG 16-18 

The Somerset County Office of 
Emergency Management will operate 
WC2ADK from 1400--0100Z each day. 
R.A.C.E.S. and Public Service at the 
annual 4-H Fair. Suggested fre- 
quencies: Lower 25 kHz of General 
80-10 meters and 10 meter Novice: 
Visitors on 1 45,320 simplex. Send QSL 
and SASe to Somerset County OEM/ 
4H, PO Box 3000 . Somervitfe NJ 
08376. 

SCARBOROUGH ONTARIO 
AUG16-SEP4 

One of Cartada's most ambitious 
amateur radio exhibits will again be 
part of the Canadian National Exhibi- 
tion. The veaCNE Exhibit will be in the 
Arts & Crafts Building. Take time to 
operate the station. Listen for VE3CNE 
on all the HP bands, apply for a colorful 
QSL card. VE3CNE Executive Com- 
mittee, 44 Innisdafe Road, Scarbor- 
ougK Ontario CANADA h4tR 1C3. 

POMONA CA 
AUG 19 

The Tri-County Amateur Radio As- 
sociation is sponsoring its Hamfest 'SB 
at the Palmares Park Recreation Hall 
at Orange Grove. Indoors, free park- 
ing, prizes. ARRL booth, VEC exams, 
admission, S3. S3 pier tatrie. S5 rKm~ 
members. No personal tables. For pre* 
registration and table reservations, 
contact WB6UFX. For exams, send 
SASE, 610, original license and copy 
of current l^icense, photo ID,. S4 to 
TCARA, %Joe Lyddon WB6UFX. 68^ 
Sard St.. Alta Lome CA 91701. (714) 
980-^^63. 

OAKLAND NJ 
AUG 19 

The 13th annual Ramapo MountaJn 
Amateur Radio Club Hamfest & Com- 
puter Flea Market will be at the Ameri- 
can Legion HaJI and Grounds. Indoor 
and tailgate vendors, VE exams, 

prizes. Tafk-in WA2SNA/R, 146-49/ 
147.49, l46,52/-55 Simplex, Details on 
WA2SNA-1 PBBS Marc WA2S 
@ WA2SNA packet o/ (201) 652- 13187 
8493. 

miACANY 
AUG 19 

The Rngers Lakes hamfest. spon- 
sored by Itie Tompkins County Ama- 
teur Radio Club, will be at the 4H* 
Acres. Admission, S3. Ureter IS, free, 
Tallgaters, $1. InckKir tables, $S each. 
Overnight camping, vendors handi- 
capped parking. Tallc-in on 37/97. Bob 
KD2ih/l A T, (607) 347^4444. 

VICTORIA TX 
AUG 19 

The Victoria and Port Lavaca Ama- 
teur Radio Clubs are sponsoring their 
annual swapfest at the Knights of 
Columbus NalL Raffle chance includ- 
ed with admission ticket. Prizes, barbe- 
cue, VEC exams* displays, and pro- 
grams for hams and rK>nhams. Talk-in 
on 145.19 {Victoria^ and 147.02 (Port 



74 73 Amateur Radio * August, 1939 



Lavaca). Gary Gamett AASJT, PO Box 
7G25, Vk^toha TX 77905: of Lynn He- 
witt K8KKD, PO Box 330, Port lamca 
TX 77979, 

TACOMA WA 
AUG 19-'20 

The Northwestern Division Conven- 
tion and Tacoma HamfaJr, sponsored 
by ihe Rad»o Club of Tacoma. wilf be at 
Pacrfic Lutheran University. Admis^ 
sion, $5 tiir Ayg. 6, $7 at door. $1 lor 
nonhams; 12 and under, free. Flea 
markets tables Si 8 (includes registra- 
tion), commercial exhibits, exams, BV 
parking (no hcokups)^ $2.60 each 
night; dormitory rooms (no reserva- 
tions required), $15 single, $22 double. 
Entertainment, banquet program, ac- 
ttvities. displays, lechnrcal seminars. 
Pacific Rim Disaster Team presenta- 
tion. "Radio Communications for the 
Armenia Earthquake/' H^m Cfub of 
Tacoma, PO Box 11188, Tacoma WA 
984fi. (206) 759^2040 or BiH Morgan 
W7GPR, (206) 53t -3821. 

HUKTSVILLE AL 
AUG 19-20 

The Huntsvtile Hamf&st 19S9 will be 
at the Von Braun C^vic Center, the site 
Of the 1989 ARBL Southeastern Dfvi- 
sion Convention Free public admis- 
sion; free etectricity in each booth; free 
coffee and doughnuts each morning; 
and free catered lunch both days* 
There is no charge for attending any 
part of the Hunts ville Hamfest. There is 
a charge for booths. Send fof infcrma- 



tion packet. AnD^vi^ W84KKA, Dealer 
Show ChafTttmi, (205} 883-04 77. John 
Morris K4XH, Assistant Chairman, 
(205} 359-3994. HuntsviKe Hamfest, 
Inc^, 2304 5. Me mo rial Parkway, 
Hunlsviiie AL 358Qt , 

W. LAFAYETTE (N 
AUG 20 

Th-e Tippecanoe Amateur Radto As- 
SQCiatfon will hold its 1 &th Annual Ham- 
fesi at the Tippecanoe Fairgrounds. 
Tickets. $3. A la/ge flea market, deal- 
ers, and forums will be featured Talk* 
in on 1 3/73. D,C. Roberts, 5124 Jack- 
son Highway, West Lafayette iN 
47906. 

TOKYO, JAPAN 
AUG 2S-27 

The Japan Amateur Radio League 
will hold their HAM FAIR '89 at the New 
HaJt (Shinkan) of the Tokyo internation- 
al Trade Center in Harumt. Tokyo. The 
two principle themes of the event are: 
enjoy Cycle 22 more fully by operating 
new bands and support the success of 
new Amateur SateUile J AS- lb. 90 
m^ufacturers and dealers, outdoor 
flea market, display of vintage trans- 
mitters. CW contests, technical fo- 
rums, do-it-yourself workroom, best 
home-brew contest display and sales 
of ARRL publications. Tickets^ good for 
all three days, are 900 yen for adults, 
400 yen for children under 15, and will 
be sold at the gate. JARL 14-B, Saga- 
ma t-chome. Toshima-ku, Tokyo 170, 
JAPAN; PO Box 377, Tokyo Centrat 



Post Office 100-9L JAPAN. Tet. 81^ 
947.8221 FAX 81-3^943^282 Teiex: 
i 23863 JAPRETAR, 

DAYTON OH 
AUG 26-27 

The Dayton Microcomputer Associa- 
tion, inc., presents Computerf est" "89, 
the 14th annual Computer and Elec- 
tronic Convention and Flea Market In- 
doors at the Hara Conference & Exhtbi- 
tton Center. Dealers, speakers and 
seminars, demon si rations, user group 
and club displays, prizes, free parking. 
Admission, $3 each day. Children un- 
der 12 free. Special offer for groups. 
(513) 263-FEST (general and vendor 
information). Mark HansUp, 143 
Schioss Lane. Dayton OH 45418 (ven- 
dor information). BBS, (513) 293- 
1754: parameters 300/1200^400. 8^ f, 
ncne^ For placing an ad, contact by 
July 31 , Dave Tayhr. 3030 Vioia Drive, 
Beavercreek OH 45385. (513) 426- 
7650. 



MARY5V1LLE OH 
AUG 27 

Ttie Unk)n County Amateur Radio 
Club announces its 14th annual 
"Marysville Hamfest'* at the fair- 
ground. Free overnight camping, en- 
tertainment by the "Ham Band/' ac^ 
mission S3 in advance, $4 at the gate. 
Indoor and outdoor flea market space 
available. The Union County Amateur 
RmHo Cfub, 13613 US 36, fi^arysvitle 
OH 43040. (5 13) 644-0468, W8BJN. 



DANVtLLE EL 
AUG 27 

The 21st annual Danville Area Ham* 
fest will be at the UAW #579 Civic Cen- 
ter. Tickets, $2; or three for $5. Talk- in 
on 1 46.82. Cookout. FCG VE testing, 
walk-ins welcoma^ Bring ID, S4.75; it 
upgrading, bring your original^ license 
and a copy to send with the 610, 
Overnight OK. but no hookups. Prizes. 
Joiin Cunningham WA9WJG. 1703 E. 
EngUsh. Danvitfe iL 61832. (217) 443- 
0100. 

LEBANON TN 
AUG 27 

The Lebanon Hamfest, sonsored t>y 
the Short Mountain Repeater Club, will 
be at the Cedars of Lebanon State 
Paf k. Outdoor facilities only, exhibilors 
bring your own tables, Talk*m on 
146. 31/. 91. Mary At ice Fanning 
KA4GS8, 4936 Danby Drive, Nashvitfe 
TN 3721 r (615) 832-3215. 

ST CHARLES MO 
AUG 27 

The St. Charles ARC will sponsor 
HAMFESTe9 at Stanchette Park, Fo- 
rums and license exams, free admis- 
sion and parking. Handicapped park- 
ing available. £2 p&r space for tailgate 
Rea market. Dealers wefcome in air- 
conditioned halls. Talk-in on 146.07/ 
.67, 444.65/449.65 repeaters and 
146.52 simplex. Mike Noian KA0UXQ, 
16 Gateswood Drive, St. Peters MO 
63376. 



m 



SUPERFEST '89 

September 16 and 17, 1989 
Exposition Gardens, Peona, Illinois 

• Featured speaker, Gordon West, WB6N0A 

• Commercial and manufacturer exhibits 

• Acres of flea market 

• Home and professional computers 

Tickets: $4 through Aug. 31; $5 Sept 1 through show 
Write: Superfest '89, P.O. Box 3461 Peoria, IlL 61614 
Call: 309-674-5656 (24-hour answering machine) 






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73 Amateur Radio • August, 1989 75 



Numtier 31 on your feedback card 



Above and beyond 

VHF and Above Operation 



C.L Houghton WBSfGP 
San Diego Microwave Group 
6345 Badger Lake 
San Diego CA 921 19 

24 GHz Operation 

Equtpment for 24 GHz seems to 
be very scarce Recently. I heard 
a new word io describe it^'*unob* 
tainium." Well, there is good 
news which I hope will put you at 
ease: you can obtain materials in- 
expensively. You may have to dig 
a little to locate surplus materials, 
but not for long. Severaf commef- 
cial systems are being conslfucl- 
ed which will contribule to Ihe sur- 
plus market in a few years. 

I know of two units you can use 
on our 24 GHz band. They are 
available Irom Microwave Associ- 
ates and California Eastern Labs. 
Microwave Associates makes the 
familiar Gunnplexer units tor 10 
GHz, and a similar unit for 24 GHz 
which costs about $350. Accord- 
ing to MA/COM, the unit's fea- 
tures are similar to the 10 GHi 
unit, it has a circulator/detector in 
the output, and varactor tuning ot 
Ihe Gunn source. These features 
are essential for a high perform- 
ance unit. 

The 24 GHz Gunn oscillator/ 
detector device, the NEC ND- 
610AAr^, is available from Califor- 
nia Eastern Labs. It is a basic 
setup intended for alarm applica- 
tfons, without the added features 
of the MA/COM device. This mex- 
penstve unit has a waveguide de- 
tector and an approx. to mw 
Gunn source (no varactor tuning). 
You can adjust the unit mechani- 
cally as well as by Gunn voltage 
tuning. 

One word of caution to users of 
10 GHz systems: You need to 
modify the Gunn DC voltage sup- 
ply to connect the 24 GHz unit to 
your 10 GHz wideband FM sys- 
tem. The 10 GHz system Gunn 
runs on a 10 voli supply, while the 
24 GHz Gunn device requires 7 
volts maximum. Accidentally con- 
necting the 1 volt supply to the 24 
GHz device wouid destroy ft. Be 
careful— one mistake is COSTLY. 

Preliminary tests on one of the 
NEC ND61 OAAM Gunn oscitlators 
prove it to be a fast way to get 
on 24 GHz with minimum cost 
($50), It's available from California 
Eastern Labs 3260 Jay Street, 
Santa Clara CA 95954. Tet. (408) 

76 73 Amsteur Radio • August. 



988-3500, Quite a bargain. 

Test Equipment Limits 

My only trouble working a! this 
frecfuency was fmding test equip- 
ment. In the surplus market, test 
equipfTidnt usually stops at 18 
GHz. Most pieces of equipment 
on my test bench are older Hew- 
lett Packard units, like the 5245 
frequency counters, which go to 
only 16 GHz. My power meters are 
rated to 12.4 GHz. With an exter- 
nal detector, my spectrum analyze 
ef can go above 12.4 GHz. This 
was the only tool 1 had for setting 
frequency. Kent Brittan WA5VJB 
found a wavemeter that covers 
the 24 GHz band, and I plan to 
keep a lookout for one for my 
shack. 

Unit operation was little un- 
stable without a circulator. Wav- 
ing my hand in front of the anten- 
na caused the oscillator to shift 
frequency quite a bit. This occurs 
on 10 GHz in simple wideband 
units, but tt was more pronounced 
on the 24 GHz oscillator, 

Commercial equipmerit tor this 
band is being made for short dis- 
tance point-tai>oint*lo*poini tele- 
phone communications by some 
companies, such as Raycon and 
MA/COM. The Raycon system, for 
short range communications (15 
miles), usually involves multi- 
plexed (many) telephone circuits 
on one microwave frequency. 
Their brochure slates that they 





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METER 


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METER 


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33cm 


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use wideband FM, and have the 
capability of 192 channels avail- 
able for two-way voice communi- 
cations on one 24 GHz microwave 
system. 

The limitations on these sys- 
tems and on amateur applications 
are the same, however. Narrow- 
band systems^ which are becom- 
ing more popular in amateur appli- 
cations, give a greater range than 
their commercial counterparts. 
Narrowband signals belter toler- 
ate a noisy path. 

However, all is not rosy. Trans* 
mission through a normal atmo- 
sphere shows an average k»ss of 
0.02 dB per mile at 10 GHz, and a 
loss of 0.2 dB per mile at 24 GHz. 
When it rains, these losses almost 
double the loss over those on a 
dry day (see Figure 1). Additional- 
ly, the loss figure suddenly peaks 
at the 24 GHz range due to Ihe 
absorption of water vapor in the 
atmosphere. Some people sug- 
gest we were given this band be- 
cause of the high loss due Io water 
vapof absorption, but other bands 
have this problem. The first oxy- 
gen absorption band Is 65 GHz. 

Fiefd Tests 

Several local amateurs bought 
equipment from California East- 



ern Labs and conducted tests be- 
tween San Diego and Los Ange- 
les, Experimenting with mobile 
operation on 24 GHz from the Los 
Angeles area produced success* 
ful results. Jack N6XO (mobile in 
Los Angeles) made many con- 
tacts with Alan Packer WA6GPL, 
who was operating from his home 
QTH. N6XQ made several suc- 
cessful contacts, from stops along 
the highway on his return trip to 
San Diego, to further test 24 GHz 
operation. Tne last 24 GHz con* 
tact on his return trip was from a 
spot near the Camp Pendleton 
USMC base, about 50 miles south 
of Los Angeles. Signal strength 
was still good, and fie made the 
contact with little difficulty. 

We made the next contact from 
San Diego from N6XQ's home lo- 
cation, a spot on Point Loma 
which has yielded good 10 GHz 
contacts to Los Angeles before. 
However, several tries from 
Jack*s QTH in San Diego on 24 
GHz to Los Angeles proved futile. 
The path is over water to Los An* 
geles for about 100 miles. We 
made 10 GHz wideband contacts 
easily, with approximately the 
same power output levels. Finally, 
after many attempts over several 
weeks, we made a two-way con- 



ao 



10 



UJ 

o 

01 



5 
2 



0.50 

0.10 
0.050 



/ 



# 






/ 






/ OKYSEN \ 

/ 
t 
f 

D 



,>0 



.^0^ 



BAI4D 



.-0' 






\ 



T / 



V 



or'" 



.^■ 



I 



I 






I 
i 

# 

# 



/ 



/ 



/ 



WATER 
ABSORPTtON 






y 



/.^< 



NOTE? 

TO PIGURE LOSS YOU MUST ADO 
NORMAL LOSS AND ANY ADDITIONAL 
RAIN LOSS TOGETHER FOR TOTAL 



± 



X 



L 



1 



fO 



20 



30 40 50 



60 



m 



ao 



90 100 



Figure J. 



1989 



continued on p. B2 



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73 Amateur Radio • Augitet. 1989 77 



MIM 



commuedfromp. 54 

can assume identical results for the transmit- 
tal signal. 

Svmmetr}' Comparlioiis 

With a symmetrical, dual-radiator antenna 
system, you can compare the two individual 
radiators. You can run listening tests by 
switching from one radiator to the other and 
often detect any defects from the outset. I 
compared each of the three radiator types— 
the dipole, COCOA-2, and COCOA-3— with 
its counterpart before progressing to the next, 
more complex configuranon. In each case, 
listening tests showed the two radiators iden- 
tical, within the 1-2 dB accuracy of the mea- 
surement method, 

Front-to-Back Measurements 

After finishing ihe icsis above, I ran exten- 
sive lisiening tests, using the foreshortened 
model, to deiermine the overall feasibility of 

ihese configurations* Front -to-back ratios for 
each of the radiator combinations averaged 
10-15 dB. Principal directivities in this in- 
stallation are in the east-west direction (ele- 
ments run north and south). However, with 
the two radiators connected in-phase, bolh 
Che COCOA-6 arrangements gave an F-to-B 
of up to 30 dB and signal strengths approxi- 



< a WHIP 



STAN Dam) 

COPPER WIRC 

rosniB 



jiuroiiorrtviE 

SPADE UUG 







COIL : # iSCCPPEfl 

(10 TVfiH^/mcHi 



Figure 8. Detail of vertical ternnnmium. 



liPUT 




■«■ tQ C0COA-« 



•l|j|li^>t2«-w>?«l' 



t4 tunna 



Figure 9* Diagram of toroidal marching 
tramfonner. 

78 7$ Amateur Radio * August, 1989 



mately 4 dB stronger for stations 10 the south , 
CMiq^ared to the single radiator of the same 
type. Repeating this comparison for the 
dipole radiators yielded only a 2 dB change, 

GaiD Considerations 

I found a loss of 10 dB for a dipole at a height 
of 12 feet, compared to an identical dipole at a 
height of 61 feel. This is about equivalent to 
the gain of a typical linear amplifier! Keep 
this in mind when evaluating data for the 
foreshortened COCOA-3 radiators. 

Figure 7 shows that the two foreshortened 
radiafors, with the high induction fields of 
their loading coils on either end of the high 
dipoles, are close enough to the ground to 
have appreciable comparative ground losses, 
perhaps in excess of 10 dB. See Figures 10a 
and 10b. Using the high dipole mentioned 
above for comparison, we see that, for a level 
COCOA-3 radiator, the effective radiation 
from the three dipoles located cotlinearty is 3 
X P/3\ or P. That is, nearly all of the power is 
effectively radiated. However, referring to 
Figure lOb, if we assume that the two low 
dipoles are each down by 10 dB in effective 
radiated power (equivalent to the 12-foot- 
high case), the resulting effective power from 
the three dipoles is only 0.4P. In other words, 
expect the output to be down approximately 4 
dB from the high dipole- 

Si^uri Strength Comparisons 

I made extensive dB comparisons, using 
the receiver nicniioned above. The east and the 
west COCOA-2 and COCOA-3 were compared 
with the opposite standard dipole using sig- 
nals at various distances and times of day. 



The signal strengths from both of the 
compound radiators showed losses compared 
to the reference dipole. Specifically, the 
COCOA-2 measured about 3 dB down and 
the COCOA-3 measured about 6 dB down, 
compared to the dipole. Recall though, that 
for the uncompromised antenna shown in 
Figure 4, if all four terminations are located 
at the highest practical height {60 ft,), the 
gain would be 8 dB over a dipole— the kind of 
gain one would expect in a 4-element rotary 
beaml 

Conclusion 

This anicle described a practical design of 
a 6-elemeni, direction'Switching phased ar- 
ray antenna system for 75 meters. This sys- 
tem features two coaxial, collinear radiators, 
each comprising three half- waves in phase. 
You can control directivity' and angle of radi- 
ation by switching delay lines in the coaxial 
feed system. A version of this system, using 
inductively foreshortened elements close to 
the ground, has been constructed and used to 
evaluate gain and front-to-back ratios. Height 
above ground is all-important! 



References 

'"A Balanced Dipole Amenna." by J,E. Taylor, 7S 
Magiizine , Ocinber 1973, page 57. 

'"A Low FncqUiCncyPki^dAnay/'t^yJ.E. Taytor^ j9 
Magazine, July 1974. page 49. Also* "An SO Meter 
Phased Array," by I.E. Taylor 73 Maga^mt, March 
I97S.p«ge52, 

' "The SO Mci«r Pile Cnisher, ' tiy I.E. Taylor, 73 
Magi^ae , June 197S. pa^ 76. 

***A Pciftable Coajcial Collinear Aniemia." by B.B. 
Balsk^' and Warner Eckitind. IEEE Transmtions on An- 
lenna^ and PropagatkHt^ July 1972. pages 513-16. Sae 
also Radio Cmnmunicmorj , September 1972, page 597. 



f 



P/3 



P/3 



P/3 



X/2 



X/2 



)^/2 



60 ft. 



77777777777777777771777777777777777777777777777777777777777777777 

EFFECTIVE RADIATED POWER: 
AJ P/3 + P/3 +P/3 ^P 



P/3 



X/2 



60 ft, 



(l/IO)XP/3 



tl/IO) XP/3 



^ Ji2ft 



X/2 x/2 

//y//////////////y//////////y ///////; ///////////////////// ////// 



EFFECTIVE RADIATED POWER; 
8J P/3+ P/30 + P/30 = I2P/30=0.4P±4 DECIBELS DOWN 



Figure 10. Calculated gain difference between a} an antenna whose three half- wave elements 

are all up a! 60 ft, and b) an antenna whose two outside half wave elements terminate at only 12 
feet above the ground. Ground absorption at low frequencies greatly reduces antenna gain. 



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73 Amateur Radio * August. 1989 79 




DVERTISERS 



Number 32 on your Feedback card 



ft.S.^ page 

355 Ace Communications 19 

1 Advanced Gomputer Control 37 
65 Advanced Electronic 

Applications 96* 

67 AEinco Electronics 4,5* 

• Amateur Electronics Supply . 35* 
314 Ameritron .... 29 

• Amplre, Inc. 75 

5 Antennas West 61 

89 Antennas West 79 

303 Antennas West 59 

90 Antennas West 61 

1 07 Antennas West - 53 

236 Antennas West 59 

304 Antennas West 77 

302 Antennas West 90 

82 Antennex , . , . ..... 67 

27 1 Antique Radio Classified. , . . 61 

• Associated Radio 31 

243AXMInc, ., 61 

360AXlVItnc B7 

158 Azimuth Corrmu nicat Ions ., 27 

• B & K Computer S7 

63 Barker a Williamson ..,..., 19 

41 Barry EEectronicsCorp. 41 

42 Bilal Company 61 

156 Buckmaster 

Publishing ., ...61,75J9* 

• Burghardt Amateur Radro . . . 93 



R.5.# 



page 



• Butternut Electronics ,,,.... 67 
356 C & S Sates Inc 43 

• CB City International 53 

157 Cleveland Inst, of Electronics 87 
343 Commpute Corp 61 

99 Communication Concepts, 

Inc 25 

121 Communications 

Eiectectronics 33 

10 Communications Specialists . 2* 

12 Connect Systems 1 

306 Creative Control Products . . 63 

1 5 Doppler Systems 40* 

112E. H.Yost... 61 

291 Electron Processing 37* 

• Engineering Consulting .... 61 

268 Etched Call Sign Cups 79 

372 G & G Electronics 47 

157 Gap Antenna Products . 83 

1 53 Gap Antenna Products ..... 83 
339 GGTE 67* 

17 GL8 Electronics 77 

72 Glen Martin Engineering 27 

346 Great Circle Maps 87 

326 GTI Electronics 77 

• Hamtronics, Inc. 21 

• Heath Co 90,91 

269 Hustler, Inc. . . ...... 25* 

354 ICOM America CV2* 

• Intercon Data Systems 67 



R.S.JV page 

245 Jensen Tools & Alioys 63 

272 Jun's Electronics ,. B9 

• K'40 19 

• Kenwood U^SA. 
Corporation . CV4,9,11J2* 

47 Link-Com 79 

278 Liltlite/CAE Inc. ...... ... 59 

• Maggiore Electronics Lab ... 45 

101 Maxcom Inc ..,,... S7* 

241 Media Mentors 19* 

241 Media Mentors . ^ 90* 

114 Metro Printing 59 

258 MFJ Enterprises ........ . 7 

348 Micro Computer Concepts .. 77 

295 Micro Cont. Specialities 79 

252 Midland Technologies ...... 63 

187 Mission Communication 

& Consultant 53 

163 MobiieMark 61 

375 Morcom International 79 

• lSl6KWQSLCards 59 

151 Naval Electronics 57 

• Omar Electronics 53 

• PC. Electronics ..., 47, 73* 

152 Pac-Comm 67 

178 Pacific Cable Co Jnc 59 

• Peoria Amateur Radio Cfub . 75 
68 Periphex 25 

378 Protel Technologies 83 

145 QSO Software 83 



continued from p. 62 

are no such RFI problems in your 
setup. You can make LI and L2 by 
winding 50 turns of /^26 wire or an 
A mid on 1-3 7-2 (red) toroidal core. 
Ml is a 50 microampere lighted 
meter for nighttime use. R1 is t6k 
fortheTR-7950. 

An optional LEO bar graph 
indicator (U3 and associated 
components) tracks the 50 mi* 
croamp meter movement. The 
LEDs are handy for checking 
noise or signal level out of the cor- 
ner of your eye on night hunts. 
Use a variety of colors to aid visi- 
bility if you wish. 

Vince built his meter amplifier 
on a pred rilled grid board. Radio 
Shack part number 276-158. 
There's plenty of room to add 
other goodies, such as the inter- 
nal attenuator from the March 
1989 "Homing In" column. Use 
sockets on the ICs for ease 
of setup and troubleshooting. 
Make the three connections from 
the radio to the box (S-meter, 
noise meter, and ground) with 
ribbon or other muiticonductor 
cable. 

Metering a Duat-Bander 

Hunts on 220 MHz are gaining 
in popularity, as are dual-band 
rigs such as the Kenwood 

SO 73 Amateur Radio • August. 



TM-621A. WA6DLQ recently 
got one and modified his noise 
meter box for use with it. The TM- 
621 A is a very compact unit with 
surface-mount components. I 
suggest you get the sen;ice manu- 
al for it, or any other rig you wish to 
modify, to aid in locating tap-off 
points. 

Nofse meter input on the TM- 
621 A comes from signal SQ~1 at 
the connector on the main board. 
With no signal, there are 0,6 volts 
present at SQ-1 . dropping to 0-55 
volts with the squelch open. This 
shift is much smaller and of oppo- 
site polarity to the shift in the TR- 
7950, so an amplifier/inverter 
stage is used. U2b and associated 
components in the inset box in 
Figure 2 replace R4-R6, connect- 
ing at points A and B. 

Tap off signal SQ-I without 
disturbing the delicate surface 
mount PC boards b^ removing 
the proper pin from that connec- 
tor, soldering the added wire 
to the pin, and then reinstaliing 
the pin into the connector and 
plugging it back in. S-meter 
pickoff for the TM-621A is at test 
point TP-1 , which has -h4.65 volts 
at full scafe. TP-1 sticks out of the 
two meter board in the TM-621A- 
R 1 in the meter amp is changed to 

1989 



1 20k because of the higher signal 
level. 

Checkout and Operation 

For initial checkout, leave U1 
and U2 out of the sockets. Apply 
+ 12 volts input, close S1, and 
measure the voltage at the output 
of regulator U3. Ef it's not close to 
+9 volts, change R13 as neces- 
sary. For the TM-621 A, adjust R1 6 
for 0.6 volts at the tap of the pot. 
Connect +9 volts to U2-1 with a 
clip lead and adjust RIO for exact- 
ly full scale on Ml, 

Now, turn off the power, remove 
the clip lead, and install U1 and 
U2. Set S2 to the "S'' position, 
and apply a strong on-frequency 
signal to the receiver. Adjust R2 
for exactly full scale on Ml. Ad- 
just R11 untfl all except the last 
LEO comes on, then slowly in- 
crease R11 until that last LED just 
comes on. 

Set S2 to the r^OtSE position and 
adjust R5 or R21 for exactly full 
scale on Ml, with the strong sig- 
nal still applied. For the TM-621 A, 
remove the signal and adjust R16 
to zero the meter. Repeat the 
adjustments of R21 and R16 if 
necessary. 

For hunting, adjust the squelch 
control in the rig to get a near zero 



R.S.^ page 

31 Radio Amateur Callbook 63 

34 Ramsey Electronics ........ 3S* 

• Reighcon Systems 63 

142 RF Enterprises _ 14,15 

254 Ross Distributing 77 

73 

Cummilative Index .... 90 

Dealers Acl 

Subscription Problems? 

(incie Wayne's Bookshelf . 68.69 

• Silicon Solutions 79 

244 Software Systems 77 

102 Sparrow Hawk 

Communications 59 

51 Spectrum Communications . 23 
183 Spectrum International 40 

• Summitek 90 

150 Ttie Radio Works 53 

115 The RF Connection S3 

136 Unadilla^Antennas Mfg.Co. . 63 

• Universal Amateur Radio ... 77* 
79 Vanguard Labs 59 

• MHV Communications 25 

191 W & W Associates 27 

38 W9INN Antennas 77 

• Wi-Comm Electronics . . 59 

• Yaesu Electronics 
Corporation CV3 

^ Adventsers who have contributed to itie Na- 
lipnal Industry Advisory Com.mittee(NlAG). 



reading on the noise meter when 
there's no signal coming in. Weak 
signals will then move the noise 
meter upscale. You*H be amazed 
how easy it is to get bearings 
on themT Switch to the S-meter 
position as signals become 
stronger and the noise meter 
tops out. 

Remember: I saidttiat there are 
two methods for noise metering. If 
you can't find a good DC take-off 
point in the squelch circuit of your 
particular VHF-Ff^ receiver mod- 
el, you can use the second meth- 
od. Tap off the noise at the dis- 
criminator and build an external 
high-pass filter, noise amplifier, 
rectifier, and meter amplifier. It's 
easier than it sounds. A schematic 
and full details are in the T-hunt 
book. (Moefl and Curlee, Trans- 
mitter Hunting — Radio Direction 
Findifig Simplified, TAB Books 
^§^2701, p. 156. Available from Un- 
cle Wayne's Bookshelf.) 

How do you hunt wher^ the hider 
is va lying the transmitter power, 
making both the S-meter and 
noise meter bounce around like 
crazy? You'll want RDF equip- 
ment that does not depend on sig- 
nal amplitude to obtain bearings. 
Well discuss such units in the 
next column. 



Letters 



Number 33 qn your Feedback card 



Hypocrites? 

First you guys comptain that 
code is an unworthy item which 
should be eliminated, then you'll 
have some article on how easy it Is 
to learn 5 wpm. I really don't get it, 
such hypocrisy [ Mhink your goal is 
to set! more magazines to the new 
hams. 

Robert Wright, Radio Officer 

US Merchant Marine 

Lt jg USNR 

Code is stiH required for the ham 
ticket, stnd as long as it is, we wtii 
run articles on how to study It. Fur- 
thermore, since some people so- 
tualiy enjoy learning and using 
code, we wilt run the occasional 
code study article ^ even when a 
no-code license comes about. 

The code controversy Is wide- 
spread, and we try to present as 
many thoughtfully conceived 
opinions as possible, pro and con 
(see "Letters" in the June issue). 
Many of us believe there should 
be some type of license which 
does not require code, but that 
does require stiffer testing in theo* 
ry and practice. 

You are right about selling more 
magazines to new hams. In fact, 
we believe every ham should read 
73 — there is something In it every 
month for everyone .. . 

Linda Reneau, Senior Editor 

Alternatives to the CW Exam 

There are many possible alter- 
natives to the CW exam which 
would enrich, rather than cheap- 
en, the ranks of operators. For ex- 
ample, why not a stringent exam 
on emergency operating proce- 
dures? How many hams today 
could, in a true emergency, func- 
tion immediately as competent, 
professional conduits of informa- 
tion between agencies and peo- 
ple? Alternative licensing mod- 
ules to the CW exam could be 
much harder than CW, and yet 
make our hobby more accessible 
to many people. 

We can no longer continue to 
see ham radio shrink, and console 
ourselves with the thought that at 
least we kept out the CBers= 
because we are also keeping out 
the people we need to attract the 
most! If ham radio doesn't expand 
and attract more of the best 
and the brightest In electronics, 
our children may never have a 
chance, 



From the Hamshack 

I have been a licensed ham for 
thirty years. Recently I attended 
an ARRL forum to come to some 
understanding of why the ARRL 
seems so dead-set against any 
attempts to replace the CW re- 
quirement. I was very personally 
disappointed in the ARRL repre- 
sentative, as he repeatedly con- 
fused a no-code license with a no- 
work-lo-get license. 

It's time all hams rallied around 
some plan to strengthen our hob- 
by and bring it into the twenty-first 
century, I think the first step on 
such a plan must mean that we 
have to make one thing very clear: 
that a no-code license should be, 
could be, and would be, a license 
that a person would have to work 
very hard for, in a dedicated and 
professional manner. 

Neil Shapiro We2KOI 
Bethpage NY 

Hear, hear, Neitf 

CW— Not Just A Filter 

It seems most people believe 
that the CW requirement is a way 
of weeding out riff-raff from our 
valued ham bands. Some argue 
that CW is out-mod ed and use- 
less compared to the new digital 
modes. 

RTTY, AMTOR, and packet, 
can be fast and accurate, but 
there's one very important fact: 
CW works during propagation 
conditions where the digital mod- 
es — even voice modes— fall 
down. How much more reason do 
you need to keep the require- 
ment? 

Ronald Scott Gray N7CTF 

Glasgow MT 

Another Success Story 

About three years ago, my 
school received a grant of $8,000 
tor a program called ''the commu- 
nications option." This meant 
constructing a radio station to 
train our students with the tech- 
niques of a disk jockey and com- 
mercial radio station manage- 
ment. After spending half the 
money, the school administration 
asked me to think of a way to 
spend the other half, and I said I 
would begin a program on ama- 
teur radio, about which I knew 
practically nothing at the time. 

I received lots of material and 
help from the ARRL and de- 
signed a course to prepare 17 stu- 



dents for the Novice exam, I 
bought a Kenwood 940 S/AT and 
accessories, f also purchased a 
tower, rotor, A-4 beam, and other 
things. 

We all studied code and theory 
from Tune in the World with Ham 
Radio, then called two amateur 
operators from Queens College 
to examine us. We all passed, had 
a big party, and assembled a 
station. 

Every one of those kids got on 
the air, made CW contacts, ex- 
changed QSL cards, and had a fot 
of fun. The following year, they all 
went off to college and took with 
them something besides a high 
school diploma. Since that first 
group, we have continued the pro- 
gram and we have just licensed 
anothen 4 students. 

Well, Wayne, this letter is to tell 
you that ham radio is not dead in 
some schools. There is also a 
loose knit group of amateur radio 
operators led by Marty Smith in 
the New York City School System. 
They are completing an amateur 
radio curriculum for students in 
the elementary through sec- 
ondary grades. 

BobWeinstelnKE2FE 
Richmond Hill NY 

What Cheekl 

You're really asking for it What 
an idea J that we should allow gay 
amateurs to use the ainwaves and 
advertise in 73. Nonetheless, I 
think the Idea is a good one, 
Wou^d you allow your advertising 
staff to refuse an advertisement 
from a group of YL hams? No? 
Then how about German-speak- 
ing hams? Or maybe even Asian 
or Jewish hams? 

The fact is pretty well proven 
that gay folks have no more 
choice about who and what they 
are than a Jew or Arab has. They 
have every rfght to live with as 
much freedom as everyone else, 
as long as they harm no one. That 
includes the right to get a license, 
to use the airwaves in accordance 
with regulations, and, yes, to or- 
ganize and meet with others of 
similar background and experi- 
ence. For 73 to print an advertise- 
ment from a group of gay hams 
(assuming the ad itself is not of- 
fensive) does not constitute an en- 
dorsement of anything other than 
the right of these people to exist. 
You do believe in that right, I 
hope. Allowing them to advertise 
in 73 would seem consistent with 
your history of backing progres- 
sive ideas. Frankfy, I was sur- 
prised and disturbed that there 
should be any question at all over 



this issue. By all means, print the 
3d, and continue to print it. Set an 
example for those people who in- 
sist on being blinded by their own 
prejudice. 

Gary Lee Phillips KA0NZ1 
Chicago IL §0640 

If we can't be blinded by our own 
prejudices, whose prejudices can 
we be blinded by? Gary, you're a 
trouble-maker. . . Wayne 

Lambda ARC 

In his "Never Say Die" column 
in May, Wayne Green asks for in- 
put from the readers as to whether 
or not 73 should run a classified 
ad from our gay and lesbian ham 
radio dub. The readers might find 
the following information about 
our club useful in considering the 
question. 

The purpose of Lambda Ama- 
teur Radio Club is to provide its 
members with opportunities for 
friendship, promote good fellow- 
ship, provide support and techni* 
cal assistance, and facilitate en- 
joyment of the hobby. We are also 
dedicated to providing public ser- 
vice and promoting the amateur 
radio service. 

Our club has assisted individu- 
als in obtaining their tickets and 
helped inactive hams rekindle 
their mterest. Our club is interna- 
tfonat, with 112 members in the 
US, Canada, and the United King- 
dom. We publish a monthly 
newsletter containing technical 
and human interest articles, and 
we maintain a lending library of 
study materials for those wishing 
to obtain an amateur radio license 
or upgrade. We sponsor member 
nets which encourage members 
to operate in a variety of modes, 
and we sponsor an awards pro- 
gram with certificates for profi- 
ciency. 

We wish to advertise in 73 sim- 
ply to reach other individuals 
who might be interested in our 
club. Our club shares at least two 
important goals in common with 
all concerned amateurs: adding 
as many new hams as possible, 
and strengthening the amateur ra- 
dio service. Last year, we in- 
creased our club membership by 
60 percent, in spite of the fact Ihat 
we have not been permitted to 
publicize our existence in main- 
stream amateur radio publica- 
tions. We are confident that we 
can do our part to turn around the 
decline in our hobby if we're given 
a chance. 

Jim KeUy KK3K, President 

Lambda Amateur Radio Club 
Philadelphia PA 19130 



73 Amateur Radio • August»1989 81 




N urn tier 34 on your Feedback card 



ECH TIPS 



TVI Snake in the Grass 

My friend's older iut>e final rig 
was driving him nuts, even though 
it seemed like he had checked oul 
all the suspect circuitry. 

He consistently overlooked, 
however, the plate chokes (56Q. 1 
watt resistors with four (urns of 
wire). I snipped the resistor choke 
wires and found one resistor read- 
ing 7Q and the other about 1 2Q. 

These things are sort of a shock 
absorber in that Ihey pass every- 
thing under 30 MHz and inducttve* 
ly stop and resistivefy dissipate 
those components higher in tre* 
quency. The problem is that the 
wattage is too low, and the "Q" of 
the surrounding wire-wound coils 
is willy-nilty. 

My solution: I replaced them 
with 2 watt units, wound with four 
turns of "solder wick/' and added 
a ferrite bead at the plate cap ends 
of the unit, I obtained the ferrite 
beads from a Radio Shack ferrite 
pack. Any bead that will slip over 
the end of a 2 watt resistor lead 
will do nicely. 



Pearls of Tech Wisdom 

Now he's on the air, and the 
neighbors are off his case. 
Terry F. Staudt W«WUZ L,P,E. 
Loveland CO 80537 

TS*d30 AMTOR Keying Mod 

(Reprinted from January '89 
NCARC CommunicBtor) First, go 
to the signal board and locate 
C500 . C500 is a 4,7 mF electrolytic 
near the center of the board (if 
viewed with radio upside down, 
with the front facing you) near con- 
nector 30. Remove this capacitor 
by twisting It with a pair of needle 
nose pfiers. This capacitor cannot 
be removed any other way without 
complete disassembly of the ra- 
dio. Its function is to debounce the 
PTT switch and is a big reason why 
the 930 will not work satisfactorily 
in AMTOR mode. 

The next step is to ground one 
leg of B476, This resistor is on the 
same board just above the large 
CW filter. The lead of R476 that is 
exposed is on the side of the resis- 
tor that needs to be grounded. An 
easy and foolproof way to do this 



is to locate R474, right next to 
R476, and scrape some of the in- 
sulation from both of the exposed 
leads and solder a bridge between 
them. Note: The leads that are not 
easy to get to are not the ones to 
worry about. 

These modifications are recom- 
mended by Kenwood and will 
prove to be very satisfactory. 

W5AU 

Removable Weatherproof ing 
for Connectors 

Every time I work on my outdoor 
antenna system, I find that I need 
to weatherproof a few coaxial con- 
nectors. After alt, coax is expen- 
sive and i don't want moisture to 
get inside of it and spoil it. 

Over the years I have used sili- 
con gfues, butyl cau^k, plastic 
electrical tape, and recently a 
shoe repair glue. All provided pro- 
tection » at least initially. Although 
the shoe glue and the butyl caulks 
lasted very well, they were murder 
to remove from the connectors 
when i wanted to open them. 

I recently came across a new 
product that weatherproofs very 
well, but allows me to open 
the coax connectors when neces- 
sary. Star Bfites^ Liquid Electrical 
Tape, available in several colors, 



is a liquid vinyl which seals 
out moisture and prevents corro- 
sion in wires, terminals, and 
connectors. It dries to a flexible 
coating. 

Star Bnte comes In a can with a 
brush applicator attached to the 
screw-on cap. Just brush the liq- 
uid onto the exterior surface of 
your coaxial connectors, being 
sure to coat ail joints and an inch 
or more of the coax sheath. Allow 
It to dry for five minutes. 

This product was tested by UL 
(Underwriters Laboratory) and 
found to offer better dielectric 
properties than plastic electrical 
tape. 

I found that it was no problem to 
remove the coating of Star Bnte 
on coax connectors with my pliers 
and a pocket knife. Porous sur- 
faces were another story, The 
coating does not come off of ihem 
very well 

Star Brite Liquid Electrical Tape 
is available in 4 fl. oz. cans for $S, 
and in 2 lb. cans for $25. The man- 
ofactorer states rt is available at 
True Value Hardware stores or di- 
rect from Star Brite, 404 1 S.W. 
47th Ave., Ft, Lauderdale FL 
33314. (800) $27^$5$3. 

Bitt Clarke WA4BLC 
Falls Church VA 22042 



continued from p. 76 

tact on a cold day, with low humid- 
ity, a condition here in California 
that we call an on-shore flow. The 
relatively dry air from the land 
mass flows out to sea, 

The 24 GHz contact made over 
this 100 mile path was poor quali- 
ty, and we didn't make a full ex- 
change. We plan additional tests, 
and we'll continue until we make 
contact. We used the simpler but 
very efficient NEC 24 GHz units. 
We consider the NEC 24 GHz unit 
to pack quite a punch, consider- 
ing its low cosL 

24 GHz Waveguide Transition 

Kent WA&VJB has come up 
with the construction of a 24 GHz 
WR-24 waveguide transition (see 
Figure 2). Kent is constructing 
a 24 GHz SSB system using a 
10 GHz IF and a 13 GHz injec- 
tion frequency to a mixer for 
generating SSB on 24 GHz. I 
will provide the construction 
details in a future column. Thanks 
to Kent and the North Texas 
Microwave Society. Be sure 
to check oul their bi-month- 
ly newsletter The Feedpomt 
(contact Wes Atchison, Rt. 4, 

&2 73 Amateur Radio * August. 



Box 565, Sanger 
TX 76266), 



•Mft-m PUftHCE 



J 



General VHFf 
UHF News 

News from the 
Midwest VHF Re- 
port is that several 
stations took ad- 
vantage of the au- 
rora during the 
VHF Sweep- 
stakes. WA90 
worked 10 states 
on 2 meter SSB. N/ 
OLL added 20k 
contest points to 
his score by making 39 contacts 
on 220 MHz and 1296 MHz. Rich 
K9D2E had a SUPER Aurora Sat- 
urday and Sunday. He picked up 
10 new grids on 2 meters and 12 
on 6 meters. 

fn Michigan, Bruce Rfttenhouse 
N81RW and Ken Hendrickson 
NSDGN have formed the West 
Michigan Microwave Group. 
They're out to shatter some myths 
about microwave operation: 

MYTH /S^l n 's orify good for Ime- 
of'Sfght operation. Not true! The 
same tropospheric scattering that 
makes QSOs of up to 500 kilome- 

1989 



I 



0.17' 



f,D. 



SI^A 



oy 



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T_L^ 







BACK WALL 
SHORT 



0.4Z"HJ.f— 




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ik 



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T 



t 



Figure 2. 

ters possible on 2 meters (on a 
dead band), is also present on 10 
GHz. Band openings occur on mi- 
crowave frequencies, too. From 
the RSGB VHF/UHF Manuai, 4th 
Edition: "There was a famous oc- 
casion in 1798 when the whole of 
the French coast from Caiais to 
Dieppe became visible one after- 
noon from the cliffs near Hastings. 
Effects such as these are even 
more pronounced at radio fre- 
quencies.** 

MYTH #2 it's expensivm. 
M81RW and N60GN are busy 
showing I heir home-brew trans- 



ceiver, which cost about $50 to 
build and works very well, at swap 
meets and clubs, 

MYTH #3 You have to be a 
Ph.D. to wori( mfcrowave. You 
don't have to t>e an RF expert to 
build a microwave station, There 
are several active amateurs in this 
country on various microwave 
bands who are not even technt- 
cians or engineers. 

I will be happy to answer any 
questions related to microwave 
operation. For a prompt reply, 
send an SASE to the atiove ad- 
dress. Best ?3s 




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73 Amateur Radio • August, 1989 83 



I 



*• 



Number 35 on your Feedback card 




INTERNATIONAL 



Notes from FN42 

Amateur Radio has a f ways 
been internatfonaf in the sense 
that poiltical boundaries, obvious- 
ly, have never been able to stop 
radio waves in midair. Today, 
however^ international broadcast'* 
ing (governmentai, commercial, 
and also private— amateur) is 
purposeful to a degree not ever 
known before; and the worldwide 
communications of * 'tomorrow/* 
meaning (n immediate future 
months and then ail future years^ 
is going to boggle our minds. 

Just as an example: As Wayne 
W2NSD/1 said in an interview 
for an article a few months back, 
*\ . in to or 15 years we'll 
[bo using} a little laptop keyboard 
for writing messages and {having} 
them delivered anywhere in the 
world in seconds, for pennies. *' 

ft is May 17, f989, as we write 
these words for the August ''73 
International/' and they are 
to remind you that on this date 
the 166 member nations of the 
ITU (the fnternational Telecom- 
munications Union) celebrated 
the 21st World Telecommuni- 
cations Day. A year from this 
date they will be celebrating the 
22nd World Telecommunications 
Day. 

We think it would be a great 
idea if Amateur Radio clubs 
around the world sctieduled some 
events in honor of international*' 
ism, little events or big ones, on or 
around i^ay 17, 1990^andletus 
know about themi If you have 



edited by C, C. C. 

sent us your plans (and pictures, if 
you can) before the end of 
February f 1990, we will be able to 
make the May 1990 issue interna- 
tionally special! See the feature 
item of this month's column, be- 
low, "Communfcatfons At The 
Crossroads/* 

Roundup 

Albania. EXCLUSIVE! A DX- 
pedltfon to Z A — the rarest of the 
rare! Not since the 1971 trip by 
Martti Laine 0H2BH has an Alba- 
nian tnp been in the news. This 
one, proposed for September of 
this year by Peter Vekinis EI4GV 
(19 rue Le Titlen, 1040 Brussels, 
Belgium; Tel: 02/ 736-3690; Fax 
03/ 271-1715; The Source ID: 
1P2006), is still being worked on — 
contact him for details and watch 
for more information. 

Austria/China. [•] (Roundup 
items marked [•] are from Sweden 
Calling DX-ers, the publication of 
Radio Sweden.) Adelegation from 
Radio Austria International went 
to China on the invitation of Radio 
Beijing and the Chinese govern- 
ment to discuss a possible ex- 
change of broadcasting hours and 
relay cooperation. 

Austral ia,[»] We may get more 
details from VKSAJU, but a flash 
for now; The new Radio Australia 
transmitter a! Brandon, Queens- 
land, had two days of use before 
along came Tropical Cyclone Aivu 
and its 200-kilo meter winds and 
put it out of business. The storm 
equalled the ferocity of I974's 
Cyclone Tracy which wiped out 



Calendar for August 

1 — Army Day, China; National Holiday, Switzerland <2nd for El 

Salvador, 9th for Singapore) 

3— Memorial Day, Cyprus; Independence Day, Niger (Sth for 

BoJivia, 10th for Ecuador, 1 1th for Chad, 14th for Pakistan, 15th 

for India, 17th for Indonesia, 19th for Afghanistan, 2Sth for 

Uruguay) 

4 — Freedom Day, Guyana; National Day, Jamaica and Burkina 

Faso (15th for Congo and Korea, 20th for Morocco, 31st for 

Malaysia and the Republic of Trinidad and Tobago) 

7 — Battle of Boyaca, Cotombla; Bank Holiday, Ireland 

12— Queen's Birthday, Thailand 

13— Women's Oay, Tunisia 

16 — Restoration Day, Dominican Republic 

20 — Constitution Day, Hungary 

23 — Liberation Day, Romania (27th for Hong Kong) 

24— National Flag Day, Liberia 

28— Summer Bank Holiday, Great Britain 

29— Heroes Day, Philippines 

30— Victory Day, Turkey 



Darwin, and reportedly killed 4 
and injured many. 

Costa Rica4*J For the third 
year in a row, the Swedish DX 
Federation has named Radio Im- 
pacto of Costa Rica ^^QSL Station 
of the Year." This shortwave sta- 
tion has answered reception re- 
ports even though it has not inten- 
tionally been broadcasting for 
listeners abroad. Its programming 
has been political and aimed at 
neighboring Nicaragua. 

Switzerland. The First World 
Book and Audiovisual Fair on 
Telecommunications and Elec- 
tronic Media will take place in 
Geneva between October 3 and 8. 
It will be associated with ITU-COM 
89, the first World Electronic Me- 
dia Symposium and Exhibition. 
Further information from; Book 
Fair W Secretariat, ITU, PR Divi- 
sion, Placodes Nations, CH-1211 
Geneve 20, Switzerland. 




CANARY ISLANDS 
(Spain) 

Woodson Gannaway N5KVB/EA 

Apartado 11 

35450 Santa Maria de Guia 

(Las Palmas de Gran Canaria) 

Islas Canarias 

Spain 

It feels time to send in some- 
thing from the Canaries again. To- 
day IS El Dia de los Trabajadores 
(Labor Day, I think, or May Day, as 
it is now called in China, France, 
Germany, and the USSR) and so 
nobody is working. 

We live In a small town on the 
NW side of the island of Grand 
Canary; the town is Santa Maria 
de Guia, It's famous for its cheese 
and as a long time supplier of the 
best of Canary knives. The ac- 
knowledged best of the few men 
still forging blades for these diS" 
tinctive knives is in his sixties, and 
f work in his shop every morning to 
learn. In the afternoons and 
evenings, I teach my English 
classes. 

I get or> the radio whenever I 
can; up to now, usually CW above 
21 .100 on 15 meters, but Tm starl- 
ing to branch out a little more. The 
old Drake covers 80-10 and I've 
dipoles for 40-20- 1 5 so far. For 
the present I have to stay on my 
long, narrow balcony, so I'm 
somewhat limited. Still, I get over 
to the US now and then with a 559 
signal (the balcony is open to the 
E, not to the W), Although no trou- 




Woodson Gannaway N5KVB/EA, 
Canary islands, Spain. 

ble to boom into Yugoslavia, it's a 
challenge to go elsewhere* 

Radio Club Cultural Gran Ca- 
naria (EA8RCT) in Las Palmas is 
proceeding with remodeling its 
meeting room and adding addi- 
tional space outside. The two ar- 
eas will be joined by large sliding 
doors to allow use of both areas 
together during the marvelous 
summer evenings when a lot of 
hams gather there. 

(A friend there also asked me to 
mention their continued whole- 
hearted participation in all 
contests, with all QSL cards 
replied to.) 

The Club de los Radioafl- 
Gianados del Noroeste (Amateur 
Radio Club of the Northwest) 
came up with and executed an 
idea a few years back — around 
1982, perhaps. Maybe somebody 
can send me a photocopy of the 
QSL card? I wanted to find a photo 
of this so bad, but just haven't 
been able to turn one up! Drat! [Do 
keep trying— -well publish itil — 
CCC] 

Members of the club, based in 
Quia and Gaidar, spawned and 
brought to fruition the idea to 
make a walk around the perimeter 
of this island with radio equip- 
ment—the radios to be carried by 
a burro. They fashioned a rack to 
balance the radios and batteries, 
with an extension out over the bur- 
ro's tail to carry the antenna. 

They secured the special call- 
sign EA8VIB (EA8 Vuelta de la 
Isia con Burro — Trip Around the 
Island With a Burro — ^ although in 
English VIB could also be "Very 
Important Burro'*) and operated 
on five bands. 

So, for five days they walked 
around this scenic island with the 
burro carrying the gear and bat- 
teries and acting as a station 
platform. A doctor went with 



84 73 Amateur Radio • August, 1989 



them— a good thing because 
there were numerous foot prob^ 
ferns (for the peopfe. not the bur- 
ro). They camped out at nighi and 
recharged the batteries. 

When they completed the cir- 
curt and were walking back into 
Guia, it was a festival day, so they 
got a rousing welcome with lots of 
people cheering and church beJIs 
ringrng! 



m^ 



:^P^ 



GREAT BRITAIN 

Jeff Maynard G4EJA 
32 Waldorf Heights 
Hawiey Hiil 
Camberley GU17*9JQ 
England 

Regular readers of this column 
will know that the 50-metre band 
became available to UK amateurs 
only quite recently. So major 
openings still capture the atten- 
tion of us aEt; indeed, the events of 
the last weekend of February 
have been described as the 
biggest 50-melre event since the 
band became available. 

Things began to look promismg 
on the Wednesday when LU5EZT 
maritime mobile was worked 5 
and 3 each way from G(0DAZ in 
Worcester (pronounced Wustah 
for intending tourists!). By Satur- 
day, things really began to hot up 
with the \/S6SIX beacon being 
heard just before 0900; this was 
quickly followed by what is be- 
ileved to be the first G to VS6 QSO 
on 50 MHz, when G4UPS worked 
VS6UP with strong signals and 
full readibility in both directions. G 
stations on the South Coast are 
also believed to have worked 
VS6TC,WA,andGU, 

Barely was the excitement of 
VS6 contacts in control when a 
number of Japanese stalions 
were heard 5 x 9 at about 0915, 
Indeed, JA4MBM was still being 
heard 5x9 at 1 100. Unfortunate- 
ly, despite the strength of the JA 
signals, there are no reports of 
two-way contacts wrth G staftons 
on this day, although G3XBY is 
reported to have worked "sever- 
at" Japanese stations. 

Back to Saturday when, at the 
time the J A stations were first be* 
ing heard. ZS6BMS was worked 
599 both ways by G0DAZ. who 
a(so is believed to have worked 
T77C (San Marino) for another 
probable first- 

Perhaps the biggest pifeup oc- 





Eddm V. Manaio DU1UJ. founder of the AsisNet 
Group, and presently QRVon 14 Jit MHz, operat- 
ing DU 1 BBS packet buUetin board mailbox. 



Lynn V. Manaio DUtAUJ, founder of the Asian 
YL-Net, on HFRTTY, ARQ, packet and SSB. 





An Using out AUL, QRV on packet VHF, 144.090 
MHz. 



David Tan 9M2DT, on 14.11 1 MHz, operating 
9M2BBS packet mailbox. 



curred when JS2tJS in Guinea* 
Bissau was working G stations 
with good reports both ways. Oth- 
er exotic DX was heard in the 
shape of TRSC A (Gabon), ZS4TA. 
and numerous VS6s added to the 
piteup. Less exotic, but neverthe- 
less welcome » DX was apparent 
from North America when the 
opening swung in that direction by 
Monday. Amongst those stations 
heard were K2QIE, VE1YX, and 
K2GAC. 

Other examples of this opening 
included the lO-metre beacon, 
VK2RSY, being heard 5 and 5 and 
a whole clutch of exotica heard 
(but not worked) including sta- 
tions from DU1, Z23, CTI. 9HI, 
HC5. and HCl. The world's QSL 
managers wtJI no doubt be busy in 
the next few months! 

If the 50 MHz opening was not 
enough> there was a major auroral 
event beginning on Monday, 
March 13th and opening up the 
whole of Europe to 144 MHz sta- 
tions. Indeed, so strong was the 
aurora in Scotland that stations 
were reporting 5 and 9 signals 
from Sweden regardless of the di- 
rection in which they pointed their 
beams. 

Stations as far north as the 
Midlands (say, between Birming- 
ham and Manchester) reported 
good contacts with the Channel 
Islands, Germany (East and 
West), Scandinavia, Yugoslavia, 
Czechoslovakia, Austha, Poland, 
Hungary, and Itaty. Stations in the 
east of England had numerous 



contacts with Russian stations, in- 
cluding those in UQ2. UC2, UR2. 
and UBS. 

The same event giving atl this 
lovely DX was responsible for a 
blackout denying communica- 
tions to the base camp of rhe ilt^ 
fated attempt by Sir Ranulph Fl- 
ennes to walk to the North Pole. 
Ten-metre contacl was eventually 
established with the base camp 
by the London Control Centre. De- 
spite the temperature of minus 40 
degrees Celsius (!) the base camp 
reported everyone to be in good 
spirits. 




PHILIPPINES 

Lynn V. Manaio DU1AUJ 
AsiaNet Packet Network 
Box $S, U P Diliman 
Quezon City 3004 
Republic of the Philippines 

[We were happy to receive this 
report from DU1AUJ: in fact; we 
are always happy to receive re- 
ports from citizens of Bit countries 
outside the USA, particularly 
when there has been a long si- 
lence from a Hambassador. Lynn 
is thought to be the first Asian 
woman to go on HF packet and is 
the only XYL station on AMTOR 
and RJTY. She is active on 20 and 
15 meters, and is active daily be* 
ginning around 1300 UTC; 



presently she handles the Asia 
YL-Net on 21. 1^ every Sunday at 

0700 ura—ccc] 

The RepubFtc of the Philippines 
has t>een a center for world news 
since the days of what they called 
*The Peaceful Revolution/' With 
all the changes in the govern- 
ment, Ihe progress of amateur ra- 
dio was not hampered. ActivitieSi 
particularly in packet related mat- 
ters, grew, and success followed 
success. 

On July 1, 1986. Eddie 0U1UJ 
with Kohjin JR1EDE founded the 
AsiaNet Packet Network. For 
several months they were the 
only stations handling traffic 
all throughout Asia, but later 
were joined fay AX4BBS (Brian 
VK4AHD) and Gil VK6AGC. This 
expanded the operations quite a 
bit, as did the next additions. 
9M2BBS (David 9M2DT) and 
YB1 BBS-Kinta. With all this coop- 
eration^ they later decided to 
movetoT4.111 MHz from 14.107 
MHz to have a good link with the 
USA. This made it possible to 
hook Into SkipNet. And with the 
efforts that these fellow amateurs 
are making, the world is helped to 
meet one common objective: to 
promote friendship and brother- 
hood. 

Locally, on VHF, there are 
many packet bulletin board sys- 
tems operating. In the Metropoli- 
tan Manila area there Is QUI BBS 
operated by Eddie DU1UJ, Art 
QUI AUL, Glenn DU1CUP. Mon 



73 Amateur Radio • August, 1989 85 




< 

Q 
a: 

< 

X 

O 
CO 




n ZS6ET 
D S42ET 
D DF4YE 



A 



^ 



PCTEA fTflAUSS 
PO BQ)0646l 

flEP OF SOirm AFHICA 






TO HEW 


M''( 


v'^ '■ 




n!^;^ 


M^iUtC 


CHSl 


















TUi 



DUtBJO. Pau( DU1P0L. Eddie 
DU1EAG, and Pete DUiPJS. In 
the south of the Philippines there 
is Den DU9EW* and in the north. 
Mo DU3MF. 

With all these BBSs in town, 
DU1UJ decided to put up a dlgi- 
peater in Tagaytay, utilizing a 
KPC-4 and IGOM 28H and 48A. 
The vast activities of this digl- 
peater is proven effective, for it 
covers most of the Luzon area — 
the biggest of the three main 
Philippines istands. 

In the Mindanao area, DUlPOL 
and 0U9BC have established a 
digipeaterat Mt. Kitanlad which is 
supposed to cover the island of 
Mindanao; and right now these 
fellow hams are negotiating for 
the establishment of a third digi^ 
peater, in the Visayas region — the 
island between Luzon and Min- 
danao. 

With these and continuing ef- 
forts, it won*t be long, we hope, 
before ail of the 7,100 islands 
which make up the Philippines are 
linked together into one, through 
the wonders of amateur radio. 




The rare DX country, Marion Is- 
lamj, Is 00 the air again, with Peter 
Sykora ZS6PT using the call 
ZS8ML Amateur Radio Spectrum 
on RSA— the Voice of South 
Africa--wi1l regularty give news of 
this operation, weekly, as follows 
(times approximate): SATUR- 
DAYS— 1345 UTC to India, the 
Far East--21S90 and 17765 kHz; 
Southern Africa— 9585 kHz; 1445 
UTC to Middle East, Eastern Eu- 
rope— 25790 and 17755 kHz; 
Southern Africa— 11925 kHz; UK 
and Europe— 21590 kHz; USA 
and Canada— 21670 kHz; 1845 
UTC to UK and Europe— 2153^ 
and 17795 kHz; 194S UTC to 
West Africa— 21590 kHz; to 
Southern Africa— 7295 kHz: to 
East Africa and Middle East— 
17795 kHz: SUNDAYS 0245 UTC 
to USA and Canada— 981 5, 9580, 
and 11 730 kHz. 

Peter will often be heard around 
1830 UTC on 14145 kHz— a good 
time to learn of the next few days' 
activities. Please do not break in 
until he has finished his traffic with 
his QSL manager. QSL address: 
2S6PT. PO Box 1387. Vanderbijl- 
park 1800. South Africa (or 
through the bureau). I( you expect 
a QSL direct, Include suitable 
postage in USSor IRCs, 



SOUTH AFRICA 

Peter Strauss ZS6BT 
PO Box 35461 
Northern ZA-211S 
Repubiic of South Africa 

News Items 

The South African license au- 
thority will consider applications 
for short-term permits from ama- 
teurs from any country holding 
GEPT Glass I- or ll-compatible li* 
censes — except Novice, since 
there ts no compatible license 
grade here. 

The South Africa administration 
has concluded bilateral agree* 
ments with 15 countries (see box). 

86 73 Amateur Radio • August, 1989 



BIUTERAL AGREEMENTS, 

SOUTH AFRICA AND: 

Bophuthatswana 

Botswana 

Chile 

Ciskei 

W. Germany (IncL W. Berlin) 

Great Britain 

Israel 

Portugal 

SW Africa/Namibia 

Swaziland 

Swiizsrfand 

Transltei 

Venda 

USA 

Zimbabwe 



COMMUNICATIONS AT THE CROSSROADS 

When Prince Henry of Prussia tried to telegraph a thank-you 
message to President Theodore Roosevelt at the turn of the 
century, it was refused because his ship's equipment was 
incompatible with that of the coastal receiving station. And 
whan the Tit^r^fc was sinking, radio distress signals to a 
passing ship went unheeded as its radio operator slept through 
the night. 

This would not happen today. International standards ensure 
worid linkages of compatible and interference-free networks 
which allow an unfettered flow of signals across national 
borders. 

International cooperation was not always necessary. When 
Samuel Morse sent the first public telegraph message in 1344, 
no one dreamed the breakthrough would actually alter life as it 
was then. Eariy telegrams went from city to city, always within 
national t>oundarles. But as communications spread from 
country to country, the need for global international legislation 
prompted 20 countries to meet in 1865. They drew up the first 
Internatfonal Telegraph Convention, the precursor of today's 
equivalent of a charter for the ITU, the Internattonal Telecom* 
munication Union. 

The 20 founding States of the ITU In 1865 were: The Austro- 
Hungarian Empire, the Grand Duchy of Baden, the French 
Empire, the Free City of Hamburg, the Empire of all the 
Russlas, the Swiss Confederation, the Ottoman Empire, 
and the Kingdoms of Bavaria, Belgium, Denmark, Spain, 
the Hellenes, Hanover, Italy, the Netherlands, Portugal and 
the Algarve, Prussia, Saxony, Sweden and Norway, and 
Wurttemberg. 

Today, the Union's 1S6 members meet regularly, countries 
talk to each other instantaneously, and airwaves circle the 
globe, but there are new challenges as the 21st century 
approaches. The speed and complexity with which people now 
communicate requires unprecedented cooperation and inter- 
national agreements involving rules for sharing costs when 
calls transmit through more than one country, harmonized 
switching and transmission principles to interconnect a variety 
of national networks, and regulation of frequencies to allow for 
satellite systems and broadcasting and mobile services for 
maritime, aeronautical, and land communications to function 
throughout the world. 

'The telecommunications industry has changed drasti- 
cally. There are more players now, with traditional users 
and providers constantly exchanging places as they mix 
and match equfpment, networks, serviceSt and information 
to provide each other with new services and business 
opportunities. . .The success of world finance and global 
trading depends not {ust on a few rules, but on the move- 
ment of goods, on financial services, and especially on 
telecommunications to support all this activity/' 

Richard £, Butler, ITU Secretary-Generat 

Last May, the 13th Plenipotentiary Conference in Nice, 
France, examined a series of crucial issues with respect to 
future challenges. Economic zones will have to be considered, 
such as the European Community in 1992, and new coopera- 
tive relationships wfthin North America and Asia. The commit- 
tee called for more results, more quickly. As one example, ft 
caNed for a new policy to cut paper flow. In 1986 60 kilopages of 
documents were produced for activities of the tnternationai TSi 
T Consultative Committee jCCITT) alone! And more pages 
pertained to others of the 438 experts (from a roster of 2,5CX)) 
who undertook 591 field missions in 1968. Last year US$31 
million was spent on projects in developing countries, financed 
mostly by the United Nations Development Programme and 
Funds-in-Trust. 



of EJeoteronics 

Acoociltdd Member Nateral Noma Study Council 





CIE is the wor[d*s largest independent 
study electronics school. We offer ten 
courses covering basic electronics to 
advanced digital and microprocessor 
technology. An Associate in Applied 
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Technology is also offered. 

Study at home — no classes. Pro- 
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benefits. 



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1776 East I7rh St., Cleveland, Ohio 44114 

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$25 in US- $36 elsewhere (U.S. funds) Licensed amateurs, or age 65 or over, upon submitting 
proof of age, may request the special dues rate of $20 in the US. $26 elsewhere, in (U.S. funds) 
Persons age 1 7 and younger may qualify for special rates^ write for application. 

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GET YOUR BEARINGS ST RAIGHT 




At last! A map dedicated to the radio amateur. Announcmg the Azimuth- Equidistant wall map from 
kthe Great Circle Map Co. 

An azimuth map provides information about heading and range to any place on Earth. Mo tonger will 
you have to guess at which way to aim your beam antenna for that rare DX- 

Each map is specially drawn witli your station at the exact center The rest of the world is spread out 
afound you. To use the map, simply find the target station and read the compass heading from the border 
oJ^ the map. To find the range » count the number of rings from the center. Each ring is spaced 1 000 miles 
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73 Amateur Radio • AugusM989 S7 



NEVER SA Y DIE 

Continued from page B 

To tm honest about it , whai we have is a govern- 
men I policy of screwing small business. Think 
alXHJi tL Both the administration and Corrgress 
are like willows, bending whatever way lobbyists 
biow. And lobbyists are paid by big business, not 
by smalL Thus small business has little control 
over the government— little say — little power. 
The government moves the way money pushes it, 
and big business has the millions to be heard— 
clearly — wiping out the faint background noise 
from small business which has only thousands to 
spend. 

Myopia— Doing Away with Tomorrow 

Worse, and you've been reading a tot about 
this lately (if you've been reading), big business is 
totally in the grip q\ the quarterly report, so ris 
goals are invariably short-range. There's no 
ptanttng of seeds possible, just reaping as if there 
ts no tomorrow, which takes care of elimmating 
tomorrow just fine. So we've avoided automation 
and updating our old fac tones; avoided technolo- 
gy's benefits. 

How far are you willing to let all this go? When 
are you going to lift your head and take a look at 
what's going on? Are you going to let America 
sink into a miasma like the horrible mess Britain is 
in? Il wasn't very long ago it used to be called 
Greaf Britain. 

Britain got into deep trouble earlier than we 
because ttie lowered Iransportation and commu* 
meat ions costs hit them sooner, being so close to 
the Continent. Their unions, abetted by labor gov- 
ernments^ refused to face the realtiy of global 
competition. Now they have millions of people 
who are out of work and may never work again. 
They have a new generation which has never 
worked and may never work — no jobs because 
the unions forced their industries to lose money 
until they closed. They fought automation and 
lost jobs. 

If t"m right, what can we do to cope with the 
changes? Can we hold back the ocean by stub- 
bornly refusing to come to grips with the ways 
technology has changed the world? We see just 
that mentality at work with Morse Code in ama^ 
teur radio. We see it tn uniorrs which Ttghl reality. 
We see it in weak government officials who blow 
with the winds from union PAG funds and lobbyist 
money from big corporations. We see it in a Con* 
gress whose priorities are (1) getting re-elected, 
(2) getting the money needed to buy re-election, 
and (8,275) doing what*5 best for the country. 

The Strength of Our Country 

Once we recognize that small business is the 
real strength of our country— and I mean smalt 
manufacturing businesses much more than ser* 
vice businesses — we can start working to build 
this strength. But won*t the economies of scaie 
always allow big business to produce lower cost 
products than a small business? Only in a few 
industries where tooling costs are enormous. 
Oddly enough, the bureaucracy which inevitably 
buikjs up in a big business, keeps it from tsemg 
able to comfjete head -to-head with the almost 
always more efficiently run small businesses So 
big business has to pull every dirty tnck it can to 
wipe out pesky small businesses. 

If we're going to have strong smafi businesses, 
we have to have people to run them and work for 
them This comes down to education. Again, un- 
less you Ve just off the turnip truck, you know that 

88 73 Amateur Radio • August, 1989 



every recent Study has rubbed our nose in how 
poor our education is compared to many other 
countries — in how much it has gone down in qual- 
ity in the last fifty years. We're not going to be able 
to compete with Korea, Singapore, Japan, Tai- 
wan and Europe unless our educational system is 
at least as good as theirs. 

The worst part otthjs is that we've been protect- 
ed against much of the potential competition the 
world could offer. The beyond-de script ion poor 
management of African countries has kept them 
from being players so tar. The same in India, 
Malaysia and Indonesia have also protected us. 
Imagine what could happen if China and Russia 
ever notice that communism has never worked 
anywhere in the world if s been tried, and stop 
hobbling their industries with government plan- 
ning! 

Using Technology in Education 

We do have the potential to come out on top of 
all this in the long run. We have the potential to 
turn things around and stop going the Britrsh 
route. That opportunity lies in being the first coun- 
try in the world to modernize our education — to 
come to grips with technology and use it for our 
benefit, instead of fighting it. 

Our teachers brag about how they have defeat- 
ed every high-tech teaching aid which has been 
offered them. They brag about kiiiing off the use 
of audio cassetles, film strips, films, video and 
now, computers. They're not going to lose their 
|Obs just because there are some more efficient 
ways of teaching. 

Did you see I he recent articles in news 
magazines about how our krds are leaming less 
and less? We amateurs are so used to talking with 
the wortd that we know pretty much where things 
are. but in a recent test 14% of the kids couldn't 
name the country just to the north of us— and 
37% didn't know what country was to the south, 

I was amazed a few years ago when I was driv- 
ing a high school senior babysitter home. I men- 
tioned that Td just had a contact with King Hus- 
sein on my radio. She'd never heard of him, 
Hmm, he's the king of Jordan. Nope, never heard 
ol Jordan. It's right next to Israel. Never heard of 
Israel, either. That's a senior here in Peterborough. 

No wonder we're having trouble getting 
kif^ interested in talking with other countries— 
Ihey don't even know they're there, That isn't 
the fault of the kids, it's OUR fault for being so 
lazy about our schools and letting them fail 
so miserably in their responsibilttles. We 
permit less than 26% of our kids to get any 
science education in high school. 

Our Novice exam calls for no more electronic 
knowledge than the average high school student 
should have learned- Instead, the exam is almost 
an insurmountable obstacle for many kids. If you 
donU think all this comes right down to you. just 
look at what's been happening with the Asian 
students In our schools. They're running away 
with all the honors and getting first crack at our 
better colleges ]ust because their parents insist 
on their working hard. 

Your grandparents or great-grandparents, 
when they came here, worked their asses off to 
make things better for therr kids. And they really 
pushed their kids to work hard. Then something 
went wrong at home. Can we honestly blame it on 
television or Or. Spock? The blame is irrelevant^ 
the question is, what can we do about all this? 

Training Kids and Dogs 
If you, as a parent or g randparent, make it your 



business to see that kids are pressured to learn — 
to excel — this will, in turn, put pressure on 
the teachers and schools to do better. We can 
force Ihem lo turn to technology to help them 
teach, to be more productive. And that's what 
technology does, it makes for more productivity. 
Getting kids interested in teaming isn't easy. You 
won't get far with punishment, so you have to 
outsmart them, if possible. You have to make it 
worthwhile to excel, 

I've a couple of greyhounds. Training them is 
much like training kids, they'll do anything you 
want as long as you convince them it's what they 
want to do. If you try to force a greyhound to do 
something, it'll just put on a martyred look and lie 
down. Punishment is completely useless. Only 
guile will win. Same with kids. 

But amateur radio today is even more relevant 
than it's ever been. It's a key to helping young- 
sters have a major advantage in life over those 
without this boost. The future is technology, so 
the more our kids can team about communica- 
tions, elecironics and computers, the better it's 
going to be for them and for our country. Learning 
geography won't hurt either. 

Here we are with electronic and communica* 
tions technology growing almost faster than we 
can follow it. We have the potential to use ama- 
teur radio as a way to invent and pioneer new 
communications systems and to inspire kids to go 
for high tech careers. It was our amateur radio 
repeaters which spawned cellular radio. Now we 
have everything we need in technology to devel- 
op a high speed automated message-handling 
system using HP, UHF, microwaves and satel- 
lites which could allow any of us to reach any 
other licensed amateur in the world tn sec* 
onds. Or are we going to continue to try to jam 
our 1930s code requirement down unwilling 
young throats, alienating the kids we need so 
desperately to get our hobby going again? 

Recognizing and Keeping Up 
with Changes 

In the *20s we heard the cfles of ''Spark 
Forever." In the '50s it was "AM Forever." Now 
it*s "CW Forever/' Will someone lift a few 
rocks and let some light in? I got a good laugh at a 
recent talk I gave. I asked hew many in my audi- 
ence were still using CW. A bunch of hands went 
up- Hmmm. Then I asked how many were using 
computers to copy it — same hands. Grve me a 
break! 

The tact is my four^pound $399 Model 100 
computer can copy code faster and better than 
the world's best Morse op, You say my t>atlehes 
may fail? Nope, they're rechargeable. You say 
the nuclear winter may make it so dark I can't see 
the LCDs? Gee, that's a big probtem^maybe I'd 
better brush up on my code so I'll be able to help 
handle the hundreds of millions of messages a 
few hundred hams will be called upon to pass. 

Tve had a good deal of success in life by keep* 
ing track of the changes technology is making for 
us. and pushing in the direct ion of the change 
instead of fighting it. But, you know. I can't think 
of any time I haven't had an "old guard'' fighting 
both me and the changes. 

I read at>out sideband in the '50s, tried it, and 
believed it was our future for voice communica- 
lions. So as edrtor ot CO and then 73 I pushed 
hard — was fought tooth and nail by AMers. In the 
'60s 1 saw solid state as the future — again was 
foyght angrily by tubes^orever hams. Was it as 
recently as t969 that the technical editor of QST 
wrote an editorial saying hams would always be 



tube people— *th at (ransistors would never be of 
much value to hams? 

in the earty *70s I saw FM and repeaters as a big 
future for us— and was fought every inch of the 
way by old guard hams, with no help from any 
other ham magazine, 

in I he m\6 '70s I saw the jusl-in vented micrch 
computer as the future. Indeed, I wrote at the time 
that I believed the microcomputer would eventu- 
ally spawn art industry as large as the autonnobile 
rndustry — to guffaws and letters beefing about 
my publishing articles on computers in 73. So I 
started Byte and a few other computer 
magazines. Did weU. 

When I read about compact discs, f again saw 
the future . . . and started D/g/faMud/o magazine. 
It's done well, too. I turned out to be right again. 
(t"s the fastest growing consumer electronic in- 
dustry in history. 

So here I am, keeping track of change — look- 
ing to see how it's affecting our future . . , and I'm 
worried. The lack of young hams is hurting ama- 
teur radio as a hobby — and it's helping bring 
about a serious drop in the number of American 
engineers, technicians and scientists. 

NO. a resurgence of young hams alone isn't 
going to save America. But without 'em we're 
going to have a lot harder time with the other 
problems.. Jike our decayed educational system, 
the high cost of college, and a tax system which is 
helping to drive manufacturing overseas, I need 
your help with the ham end. I'm working on RPl to 
provide a proven way to get college costs cut in 
less than half^and Jordan to develop a new and 
much more productive educaik^nal system for 
kids. 

Updating Nam Radio 

Changing the ham requirements from a 
demonstrated Morse Code skill to a tougher tech- 
nical entrance exam is just one step I believe we 
need to take to keep up with technology. I don*t 
expect that's going to uncork any large scale 
youngster interest in hamming by itself — it'll )ust 
help us make more sense to them once we get 
their interest. We stiff need radio clubs in schools 
and a campaign to get kids interested in the 
excitement hamming has to offer. 

Ves, I know all about kids not being excited 
about hamming because they see international 
television programs every day. Baloneyf The fun 
of personally talking with people anywhere in the 
wofid — or anywhere around town — beats the hell 
out of CB. CompuServe. Play net and TV. It does 
for you, doesn't it? So why do you thmk you are so 
different? 

How have you been handling change? Fighting 
it or embracing it? 

Tlie Time Warp 

I've some letters from old-time hams who are 
firnous that a copy of 73 now costs S2.95 and a 
subscription $20. Good grief, they say^ it used to 
be 37C and $3 a year! And it used to t)e a lot latter. 
Come on here, what are you doing to us? 

Apparently the Caner years' trauma has wiped 
out all recall of a most memorable inflatbn, leav* 
Ing no lasting impression on these OTs. Look, 
we've had almost thirty years of inflation since I 
started 73 back in 1960, and we haven't had any 
deflation. Haven't you codgers noticed that ev- 
erything cosis more? 

Eisenhower said it clearly when he promised 
the government would tax us in dollars for social 
security and pay us back with dollarettes. So to- 
day we're spending Monopoly money when we 



go to the store, A nickel subway ride is a buck. A 
nickel cone is over a buck. That 37c copy of 73 
should cost at least S7,S0 a copy today. 

Well, what looked like a fat magazine at 128 
pages in 1960 now looks like a pamphlet because 
scientists have invented new. lighter, and much 
thinner paper. Maybe you haven't noticed tt^ 
way magazine pages stick together now They're 
down to about one RCH in thickness. 

Ham Day 

Ham Radio Day— the first Saturday in Decem- 
t>er — is alive and growing . How at>out your club 
mounting a major PR offensive next December. 
YouVe gol lots of time to plan (or it, unless you do 
as usual and put it oft until late November. 

The idea is to set up a ham station in a public 
afea — like a mall^and do two things. First you 
want to be able to hook into the national traffic 
network to deliver worthless messages— proba- 
bly using packet, wh ich seems t he way the NTS is 
going these days. Second, and much more im- 
portant, you want to have an exhibit which will 
show people who never heard of amateur radio 
some of the things we do which are fun — so you 
can interest passer's by in the hobby. Lei's see if 
we can drum up some interest, particularly with 
kids. This means the exhibit (s) have to be fun 
oriented and not the usual eclectic snob stuff 
which teiis people this is too complicated for them 
fo ever understand and also too expensive. 

The Evolution of 73 

In 1960 we used 60-pound per ream of a starr* 
dard paper stze. the most popular magazine 
stock. As paper prices went through the roof, tfie 
paper companies had to make lighter and lighter 
paper, from 50-pound 10 48. down to 45, 42 and 
now most magazines use 40-pound! This makes 
the same number of pages much thinner and 
lighter, and keeps the cost of both paper and 
postage down. 

Old-timers probably haven't noticed that the 
magazine size has increased b^ 73%, from the 
oid 6 ' K 9'^ size to e.5'^ x 11 r ThatVs 1 .73 times as 
much page space. That makes a 1 16-page issue 
today equivalent to a 20D-pager In the old sFze. 

That's not all. Again, in order to keep the cover 
and subscription prices low. all magazines have 
had to increase the percentage of advertising 
pages per issue, (n the early days of 73 we ran 
around 35% ads. Today a magazine js m trouble it 
it runs much (ess than 50% advertising. 

So* if you don't mind paying S7.50 per copy or 
S60 a year for a subscnpijon, adjusted for infla- 
tion, we can go back to the small, heavier- weight 
magazines with fewer ads. Please let me krK>w. 

Amateur radio is a whole bunch of fKsbbies, so I 
try to cover as many of them as I can in 73. Con- 
struction projects (more than the other three 
magazines combined), technical articles to keep 
you up with the state of the ad. antennas, DXing 
(our DX Dynasty Award is the most difhcutt there 
is), packet, RTTY» SSTV, weather satellites, OS- 
CAR, repeaters, UHF, contests and certificates, 
FCC actions, club activities, and ham potitics. In 
my editorials I tell it as I see it, even when this means 
attacking some deeply held ham religious beiiefs. 
such as the sanctity of the Morse Code test. 

Anyway, I think we Ve done well to keep the 73 
price as low as we have. The equivalent price today 
is more like a 15c cover price in 1960. Hey, if you 
would like to pay 37c again, adjusted for inflation, 
1 can give you a 200 page magazine every month, 
t love the idea, but do you really like the idea well 
enough to pay $60 a year for a subscription' 



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CIRCLE 272 ON READER SERVICE CARD 

73 Amateur Radio • August. 1989 aS 



BAHERIES 

Nickel-Cadmitfm.Alkaline. Lithium. Etc. 
INDUSTRIAL QUALITY 



YOU NEED BATTERIES? 
WE'VE GOT BATTERIES! 

CALL US FOR FREE CATALOG 



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2 fTi«f«r bAf>d Gun eqiflvaleft to a 4-«hemfrr^ 
¥401 All «lfrm«f[t£ and 1fr#d Irw w^th BNC 
coimcrtcir Mor* irsicto a 3 ft boom. An idaal 
fifn«rgarcY antenna, baci^packabla (1 S oz }, 
Cpeneira^l litkj usv with icc^sscwy mast Uorwy 

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CIRCLE 3Q2 ON READER SERVICE CARD 



73 in 1988 



Htjw dflcn have yrtU asked younwlf. "Where did I see an 
■irtick/revjev^ cmi ihai rig?'' Or Wjini^ in locate a fqhulnuii 
aniclc but cutild renKtnIxT cmty ihc ruimc of\hc author aiuJl''or 
c^tl^ilfn! 

Nou' you havt in encetlent refioiifist— ^^s campTled ]nd£% 
for I9S1^, Hii^ ii ■ attnpli:ie lining df aII of our [cvicK>. 
fiaameA. nui columns, afid a comf^lne kcyvi^onJ Listiiif fur 
eva> ii&iiK tnitn Jainuir) ilunugh Decens^er 19^. 

The indet ii^ ivuLalhk m i primal fDnnai^ oa an MS-DOS 
5^' fh^py dak lASCIl ibmulK or by diira uph3HJ (hav^ 
yauT rrcdil ord numlxr ready} Tlie hutl-oopjr a two dolLin. 
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ti88 TniteY 

Forest Roud 
Hancijck, N}f f).U49 



CIRCLE 241 ON READER SEAVIGECARD 




QW receive or 
leave messages 
with other local hams 
using the 16K Bulletin 
Board featured on the 
sniiillesi VTsC available —I 
the Heath^ HK 21 
Pocket Packet. 

The BBS operates 
under your call with 
simple cominaiids 
like Send or Write a 
message, Kill a message 
and read the File 
messagfrs currently on 
the s\'stem. And the 
HK 21 Pocket Packet is 
fiill} INC-Z compatible. 

Hookup is easy. 
Plyg in supplied cables 
instanth' to most 



UT% or wire a separate 
cable into vour mobile 
t]r base Ytif or UHP 
rig. Connect your 



Get your 
message 
across... 
even when 
no one is 
listening. 



"^i:/"^ 



computer via RS-232 

and you're ready to call 
a fast-grt)wing number 
of packet hams. 

Tile HK-2 1 Pocket 
Packet requires only a 
single i2\T>C@40mA 
powder source or as 
tittle as 29mA from an 
optional HKA'21-1, 
internallv mounted 4.B 
TOll, 120mAh,N!CAD 
batier^\ 

The Heath* HK- 
21 Pocket Packet — 

$219.95 !^f;^> 

To ordcr^ caJl 
1 80O253O5"'0 

For information on 
Heaths complete 
line of amateur radio 
products call 
1-800-'* i HEATH 
for your FREE 
Ileathkit'^ catalog. 




A eubsldlarj" of Zen i 

El 'lies Corporaiif iTi- 

C'ivijy, Heath Cumpany 




Best to start with. 
Best to stay with. 

Heath Connpanv 

Benton Harbor, Ml 49022 



H 



Number 36 on your Feedbick eard 



AM HELP 



Your Bulletin Board 

We are happy to provide Ham Hefp ttstmgs tree, on a 
space avaiiabfe basts. Pfease type or rmatfy print 
your request on a fuf^sw sheet of paper. Use upper 
and kmer case ietters — rwt ait capttafs. Be sure to 
print numbers carefulty. A '^r'and'T*: ''T'and "V 



0t*T and other numbers and letters can be easity 
misread when they are not printed clearfy. "U" arid 
"Vcan ^so be confused. Thank you for your coop- 
eration. 



1 need an operating manual and/or sche- 
matic for a Heathkit HR-10. 1 will pay all associ- 
ated costs for a copy, or I will copy and roturn 
the original Thank you. Wamant Patrick 

736 Raymond 

St. Jaan, Quebec 

CANADA J3B 4YG 

I need inslrudion manual and schematic for 
Southcom SC-102 Thunderbird transceiver. 
Also need 1 2 voU P/S for same. Will pay. 

Dick Beckham W7i=^M 
IBSd Hibiscus Circle 
St. George UT 84770 

I need a copy of the July 1968 article in 
Hartds On Etecironics magazine about the 
"mini-receiver*' using the Radio Shack 
TDA7000 IC. Will pay postage and copying 
costs. Thanks- Scott A. Litttin NftEDV 

921 Raton Court 
Manitowoc Wl 54220 



Upda tes 



AMPIRE and 
PROCOMM/D1GITREX 

The May 1989 review of the Ampire 146-OS 
did not include a phone number. It is {612) 
425^7709. 

Please correct the phone number in the 
April 1 989 review of the Wideband Supercone 
antenna. It is (805) 497-2397. 

Unfcfen Mod 

Refer lo the Uniden mod correct ion in June 
*'QRX/' Change the referenced resistor R39 
to R93. 

Double Oops 

We finally have it right this time — Al Mis- 
unas' call is WA2RL0. not WB2RL0 as listed 
in the March 1989 QRX column, page 14, or 
the May 1989 QRX column under "Errata/* 
page 10. 

Slliconix Makes Power FETs 

Refer to the sidebar "What Is MDS-Pow- 
er?*' in the article "220 MHz Amp" in the June 
*89 issue, on page 40. Ed Oxner K86QF from 
Sillconix wrote lo correct us. Although Sili- 
conix sold the RF power MOSFET product line 
ro M/A-COM PHI. Inc.. in 1983. ihey still pro- 
duce a large range of power FETs, as outlined 
in their MDSPOWER catalog. 



90 73 Amateur Radio • August, 1989 




Xing, contests, pile- 
Lips, traffic handling. 
When you need to command 
attention, you will with the 
SB' 1000 Linear Amplifier Ixom 
Heath. And ) ou'll do it for a cost 
that no one else can match. 

From our recent DX-pedition 
to Taiwan, operators easily 
controlled pileuj^ with die 
SB-tOOO and nothing more than 
a dipole antenna. Tliis means 
that when conditions are tough, 
you know you can depend on 
your SB' 1000 to liit voixr signal 
abo\ie the rest. AXliether 
)'Ou re using a dipole or 
stacked nionoband licams. 

Proven output power 

We don't play games by 
using old rating methods to 
make you pay for input 
power you don't get at the 
antenna. \X1iat you do get is 
1000 watt output of peak 



^ 




Heathkit 

SB-IOOO LINEAR AMPLIFIER 



envelope power on SSB and 850 
w atts on CW Even 500 watt 
output on RTTY- 

On the chance that someone 
might doubt otir claims, at 
hamfests we demonstrate that 
with onl^^ 80 to 100 1;^ atts of 
dri\Te, our SB- 1000 develops 
more output than even the 
worid-famous Heath SB- 2 20! 

Designed for toda}\ tlie 
SB-1000 offers quiet, compact 
tabletop operation at rated 
output, Thafs only 17dB (or 
about V5 of an S-unit) below 



for less than 

80 cents 

a watt 



the maximum legal power 
limit. 

"I built it myself!'* 

Because you build the 
Heathkit SB-1000 Linear 
Amplifier yourself, you not only 
enjoy cost savings, you have the 
unique opportunity' of imowing 
your equipment inside and out. 

A top qualit)^ amplifier, cost 
sa\'lng5, bragging rights, plus 
industry -recognized Heathkit 
manuals and technical assist- 
ance from our licensed ham 
consultants, should vou ever 
need it An offer thafs hard 
to pass up. 

See the SB-1000 and our 
complete line of amateur 
radio products in the Spring 
Heathkit Catalog. Call today 
for your free copy. 

i-800-44-HEATH 

(1-800-444-3284) 



>^ 




Best to start with. 
Best to stay with. 

Heath Companv 

Benton Harbor, Michigan 49022 



i 

i 


■/ 


f/ i ■** 


1 




1 


\ 1 /. " 







® 1989. Heath Compaof. 

Hcathkti is a rcgisirrrd 

trademark of Heath Ounp^m v 

A subsidiiin' ofZcfiith 

Hcctronics Coiporatiun. 



MULTIMETER 



PLATE 

CURRENT 

HIGH ^ . 
VCN-TAGE 



pomm 



TIUNSIIHT 



PWR 






Number 38 on your Feedback card 



DEALER DIRECTORY 




Burhank 

Free QSL Cards on arders over $1001! Discount 
prices on ail amateur prtidiicts. Open 7 tiays a week. 
Call our Bulletin Board. A-TECH ELECTRON- 
ICS, 1033 Hollywood Way, lurbank CA ?1505; 
mm 845-9203, (818) 846-2298 FAX, (S18) »46- 
6746 Modem/BBS. 

San Diego 

Hard to find parts, surplus electronics, standard line 
items. Hams, hobbyists, industrial professionals— 
from nuts & bolts to laser diodes ►..Electronically 
speaking. Gateway *s got it! M-F 9-5:30 Sat. 9-5. 
GATEWAY ELECTRONICS, 9222 Chesapeake 
Drive, San Diego CA 92123; (619) 279-6802. 



COLORADO 



Denver 

Hard to find parts, surplus electronics, standard line 
items. Hams, hobbyists. Industrial professionals— 
from nuts & bolts to laser diodes... Electronically 
speaking. Gateway's got it! M-F 9-5:30 Sat. 9-5. 
GATEWAY ELECTRONICS, 5115 N. Federal 
Blvd. ^32, Denver CO 80221; (3<I3) 45g-5444. 




New Castle 

Factory authorized dealer! Yacsu^ ICOM, Ten-Tec, 
KDK, Kenwood, AEA, Kantronics, Santoc. Full 
line of accessories. No sales tax in Delaware. One 
mile off 1 95. DELAWARE AMATEUR SUP- 
PLY, 71 Meadow Road, New Castle DE 19720; 
(302) 328-7728, 




Preston 

Ross WB7BYZ has the largest stock of amateur 
gear in the Intermountain West and the best prices. 
Call mc for all your ham needs. ROSS DIS- 
TRIBUTING, 78 S. State, Prestim tB 83263; 
(208) 852-0830, 




Wellington 
Wc have it! ASTRON, BUITERNUT, ENCOMM, 
HEATHKIT, GORDON WEST, KANTRONICS, 
LASER COMPUTERS, MFJ, RADIO SHACK, 
TEN-TEC, VALOR ANTENNAS & more. Small 
town service with discount prices. DANDYS, 
120 N. Washington, WelUngton, KS. 67152, (316) 
326-6314. Circle Reader Service 263 for more in- 
formation. 



..^WSPI! 



MISSOURI 



-ppppp^r 



SL Louis 

Hard to find parts » surplus electronics, standard line 
items. Hams, hobbyists, industrial professionals— 
from nuts & bolts to laser diodes... Electronically 
speaking. Gateway's got it! M-F 9-5:30 Sat. 9-5. 
GATEWAY ELECTRONICS, 8123 Page Blvd., 
St, Louis MO 63130; (314) 427^-6116. 



NEW HAMPSHIRE 



Derry 

Serving the ham community with new and used 
equipment . We stock and service most major lines: 
AEA, Astron, B&W, Cushcraft, Encomm, Hy- 
Gain, Hustler, ICOM, Kenwood, KLM, Larsen, 
Mirage, Moslcy; books, rotors, cable and connec- 
tors. Business hours Mon.-Sat* 10-5, Thursday 
10-7. Closed Sun. /Holidays. RIVENDELL 
ELECTRONICS, 8 Londonderry Road, Derry 
NH0303S; <603)434"^S371. 




Lyndhur^ 

A full service Ham Radio Store! Discount sales 
and service on most major brands. Monday to Friday 
12:00am to 7:00pm, Saturday 10:00am to 4:00pm 
U mile south of Rt.3. ABARIS SYSTEMS, 
227 Stnyvesant Avenue, Lyndhurst NJ 07071; 
(201) 391-7887. 




Jamestown 
Western New York's finest amateur radio dealer 
featuring ICOM -Larsen- AEA -Hamtronics- 
Astron. New and used gear. S am to 5:30, Sat. and 
Sun. by appointment. VHF COMMUNICA- 
TIONS, 28ft Tiffany Ave., Jamestown NY 14701, 
(716) 664-6345^ Circle Reader Service number 129 
for more information. 



Manhattan 

Manhattan's largest and only ham and two-way 
Radio Store. Featuring MOTOROLA, ICOM, 
KENWOOD, YAESU, AEA, SONY, UNIDEN, 
etc. Full stock of radios and accessories. Open 7 days 
M-F, 9-6:30 prn; Sat & Sun, 10-5 pm. We ship 
worldwide. BARRY ELECTRONICS, 512 
Broadway, New York NY 10012; (212) 925-7000. 
FAX (212) 925-700L 



NORTH CAROLINA 



Greensboro 

9a.m, to 7p,m, Closed Monday. ICOM our special- 
ty-Sales & Service. F&M ELECTRONICS, 3520 
Rockingham Road, Greensboro NC 27407; (919) 
299-3437. 




Columbus 
Central Ohio*s full- line authorized dealer for 
Kenwood, ICOM, Yaesu, Ten -Tec, Info -Tech, 
Japan Radio, AEA, Cushcraft, Hustler, and But- 
ternut, New and used equipment on display and 
operational in our 4(X)0 sq,ft. store* Large SWL 
department, loo. UNIVERSAL AMATEUR 
RADIO, 12B0Ajda Drive, Reynoldsburg (Colum- 
bus) OH 43068; (614) 866-4267. 



PENNSYLVANIA 



Trevase 

Authorized factory sales and service. KENWOOD. 
ICOM, YAESU, featuring AMERJTRON, B&W, 
MFJ, HYGAIN, KLM, CUSHCRAFT, HUS- 
TLER, KANTRONICS, AEA, VIBROPLEX, 
HEIL, CALLBOOK, ARRL Publications, and 
much more. HAMTRONICS, INC, 4033 
Brownsville Road, Trevose PA 19047; (215) 357- 
1400. FAX (215) 35S~895g, Sales Order 1-800- 
426-2820. 




Dallas 

In Dallas since 1960^ We feature Kenwood, 
ICOM, Yaesu, AEA, Butternut, Rohn, amateur 
publications, and a full line of accessories. Factory 
authorized Kenwood Service Center, ELECT^RON- 
IC CENTER, [NC, 2809 Ross Ave., Dallas TX 
75201; (214) %9-1936. 

Houston 

Hard to find parts, surplus electronics » standard line 
items. Hams, hobbyists^ industrial professionals^ 
from nuts & bolts to laser diodes ...Electronically 
speaking, Gateway^s got it! M-F 9-5:30 
Sat, 9-5 GATEWAY ELECTRONICS, 9890 
Westpark Drive, Houston TX 77063 j (713) 
978~6S75< 

South we^ Houston 

Full line of Equipment and Accessories, in- 
house service^ Texas #1 Ten Tec Dealer! 
MISSION COMMUNICATIONS, 11903 
Aller-Clodine, Suite 50O, Houston TX 77082; 
(713) 879-7764. 



DEALERS 

Your company name and message can contain up to 25 words for as little as $300 yearly (prepaid), or $175 for six months (prepaid). No 
mention of mail-order business permitted. Directory text and payment must reach tis 60 days in advance of publication. For example, 
advertising for the April '89 issue must be in our hands by February IsL Mail to 73 Amateur Radio, Donna DiRusso, Box 278, Forest 
Road, Hancock, NH 03449. 



92 73 Amateur Radio * August, 1989 



Keyword index 



Number S9 on your Feedback card 



Issue ^347 



* m * * ■€ * •*■ «■ 



10 GHz .. 

24 GHz .. 
555 timer. 

1468 quad line driver 10 

1469 quad line driver IC 

w * T ■# ■ T ill ■ I- -e- ■■ 3' * c ■*'*»«#''■■ ^^mf ^ 

74LS04 hex-inverter 

AA6CQ/VE6, David G. Hart , 
AF8B. Don Norman 

AFC unit ,,,,.. 

AFSK generator . ...... 

Ameritron, fnc ,.,,,. 

AMPIRE 

AMTOR 

antenna, vertical 

Argonaut , 

battery charging .......... 

California Eastern Labs 

coaxial cable 

col linear antenna . . .,^ * , . , . . 
Commodore 24/VIC 20 . , , . . 
connector wealherproofing . , 

WWH u ^ r . , . , I. . . . « . . 

CuSlicraft416T. ,. 

Cushcraft AOP-1 

data controller 



49-52 
.. 76 
.. 73 
.. 34 
. 34 
.. 20 
50, 73 

. . i^V 

■ . ^^ 

42 
.. 53 
.. 60 

90 
..64 
20,22 
42-43 
-. 72 
,.10 
72-73 
.. 78 
55-57 
.. 24 
.. 16 
.. 62 
.. 13 
.. 64 
.. 64 
,, 18 



DB-25 connector 18 

dipoles - 24 

Ooppfer 5hift problems . . , . 44 

education^ teaching AR . . , . 46-47 

electricity . . . , . . , 6 

FM demod circuit 46 

GaAsFET 49^52, 64 

GalaxySMKII ,.. 53 

Gel/Cell , . . . , , . . 72 

Havana Moon 31 

HB9DU, Ruedi Mangold 46 

HW^ . , 72 

IC-02AT/MFJ 1 278 hookup ... 58 
IC-2AT/MFJ-1270 interface .... 58 

IF shift mcxi 53 

interface, computer/radio 

34-37 

KK>V. Joe Moell PE . . , 62 

Kantronics, Inc. , , , , . 18 

KAM 18-22 

KBiUM.MtchaelGeier 65 

KB2eQK. Walter Symczyk .... 48 

KC4IQP, Dorothy Livsay 17 

KG5CS, Diane Magen ........ 17 

linear amp 28 

LM317.,. 49,72-73 

LM3S0 , , 73 

LM386 38 

MGF-1402 ,.... , * . . ... . . 49 

Microwave Associates .... 76 



Microwave Components 52 

microwave equip 76 

microwave op , . 49-52, 76^ 82 

Mitsubishi .....,, 49 

mobile/portable operation 

64 72-73 

Motorola MV 1872 63 

N6UE. Ray Isenson 13 

N71HY, Debra Davis , 10 

N7IPY, William Waters 34 

packet/voice switch _ . . 58 

Part 97 revision , 10, 66 

PL tone generator. . 13-16, 40 

PL-259 connectors ....,,,,. 55 
PROCOMM/DIGITREX ....... 90 

propagation 95 

Rad-Com 37 

Ramsey COM'3 , .,•..•.,... . 32 

Ramsey SR^I 38 

Ramsey Electronics 32, 38 

RTTY 20, 22 

satellite newsletters . , ♦ ^ 64 

schematic reading, how-to 65 

service monitor 32 

Ssgnetics NE602 38 

SMAconnectors 50. 52 

SO*239 connector 30, 40 

solar power 72 



Switzerland .,i . . . , . 46-47 

SWR 55-57 

Tiare Publishing ......... 31 

TO-220 72 

TS-930keymod 82 

TS-940S - 20 

TVI solution . - 62 

UA3CR, Leonid Labutin ....... 10 

Unlden mod ,,., 90 

voltage/current limfting 72-73 

WflWUZ. Terry F. Staudt, LPE 

W1FYR. Alan C. Meffill 26 

W20ZH, James E. Tailor 24 

W3L0Y. Ed Clegg 31 

W7XU, Ariiss Thompson . . 56 

WA2LQQ, vem Riportella 10 

WA2RL0, AJ Misunas 90 

WA3AJR, Marc I. Leavey. M.D, . 60 

WA4BLC. Bill Clarke , . 82 

WA52IB, Andy MacAllister .... 64 
WB6IGP, C.L Houghton ... 49, 76 

WB6RQM, Brian Lloyd 18 

WB6N0A, Gordon West 10 

WB8VGE, Mike Bryce 72 

WB9RRT, Larry R. Antonuk. . . , 32 
weak signal detection 62, 80 

Yaesu FT780R .............. 64 




BULLICTIW 



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NOW! 



Your Ham Dollar Goes 

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CALL OR WRITE FOR SPECIAL QUOTE 



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In 1937, Stan Burghardt {Wg)IT}, because of his intense interest in 
amateur radio, began selling and servicing amateur radio equipment 
in conjunction with his radio parts business. We stand proud of this 
long-tasting tradition of Honest Dealing, Quafity Products and 
Dependabte S-E-fl-V-/ C-E 7 

Above &ftp we liilly intend lo carry on this proud tradition with even 
more new product lines plus the same "fair^" treatment you've come 
lo rely oo. Our reconditioned equipment is of the finest quafity with 30, 
$0 and even BO-day parts and labor warranties on selected pieces. 
And always remember: 

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Number 40 on your Feedback card 



ARTER 'N' BUY 



QSLs TO ORDER. Variety of styles, 
colors, card slock. W48PD QSLs, PO 
Drawer DX, Cordova SC 29039. 

BNB260 



THE DX'ERS MAGAZINE Up-to-date, 
informative, interesting. Compiled and 
edited by Gus Browning W4BPD, DX- 
OC Honor RoH Certificate 2^. Send 
for fr&e sample and subscription infor- 
mation today. PO Drawer DX, Cordova 
SC 29039. BNB261 



OSL CARDS— Look good with top 
quality printing. Choose standard de- 
signs or fully customized cards ^ Better 
cards mean more returns to you. Free 
brochure, samples. Stamps appreciat- 
ed, Chester QSLs, Dept A. 310 Com- 
mercial. Emporia KS 66801 . BNB434 

SUPERFAST MORSE CODE SU- 
PEREASY. Subliminal cassette. $10. 
LEARN MORSE CODE IN 1 HOUR. 
Amazing new supereasy technique. 
$10. Both $17. Moneyback guarantee. 
Free catalog: SASE. Bahr, DepT 73-8» 
1196 Citrus, Palmbay FL 32905. 

BNB531 

ELECTRONIC KITS & ASSEMBLIES. 
For our latest catalog. SASE (45c} to: 
A&A Engineering, 2521 W. LaPalma, 
#K, Anaheim CA 92801 . BNB624 

HT-CLONE BATTERIES: ICOM: BP- 
38 Double SP3 "Wall Chargeable" 
$43.95, BP5 $42.95. YAESU; FNB2 
$21.95, SANTEC: 142M42/1200 (3 
Pin) $22.95. "REBUiLDING: SEND- 
LTR PACK" Icom BP3 $20, BP5 $28, 
BP7/S $34. BP70 $30. YaesLT FNB4/4A 
$37, Kenwood Pe21 $18. PB25/H/26 
$28, T-T 2991 $28. "U-DO-lT REPAIR 
INSERTS'^ ICOM: BP2 $18.95, BP3 
$16.96, BP5 $22,95. BP7/BP8 $28.95, 
KENWOOD: PB21 $12.95, PB24/25/ 



26 $19.95. AZDEN 300 $19,95, YAE- 
SU: FNB4/4A $32.95, TEMPO; 
81,2.4,5,15/460 $22.95, 12V/5Ahr 
PORTA-PAC W/CHGR $49.95. "AN- 
TENNAS" 2MTR 5/8-Tel/BNC $1 8,95, 
"TELEPHONE / PAGER a COMMER* 
CIAL PACKS" "FREE CATALOG." $3 
Shipping/order, PA -h6%, Visa^M/C 
+ $2. {814) 623^7000, CUNARD AS^ 
SOCIATES. DepL 7, R.D. 6 BoK 104, 
Bedford PA 15522. BNB628 



ROSS' $$$$ NEW August SPE- 
CIALS: KENWOOD TS"140S $784.90, 
TW-4100A $459.90, TM-2530A 
$405.90, TM-3530A $344.90, TM-401 B 
$334,90; HAL PCt-2000 $429.90, CT- 
2100 $499.90, DRAKE 7000E $369.90, 
ROBOT 800H $299.90, 600 $299.90. 
1200C $1235.90. ICOM IC-38AW/TTM 
$338.99, IC'45A $289.90, IG-32AT 
$539,90, IC-725 $809.90, YAESU FT- 
711RH $369.90, FT-411 $336.90, FT- 
109RH $276.99. FT-209RH $276.99, 
FT-73RTT $289.90, FT'33RTT 
$299,90, CUSHCRAFT 124WB 
$41 .50, 230WB $234.90, A4S $353.90, 
ALL LT.O. (LIMITED TiME OFFER) 
LOOKING FOR SOMETHING NOT 
LISTED?? CALL OR WRITE, Over 
8780 ham-related items In stock for im- 
mediate shipment. Mention ad. Prices 
cash, F.O.B. PRESTON, HOURS 
TUESDAY-FRIDAY 9:00 TO 6:00, 
9:00-2:00 P.M. MONDAYS. CLOSED 
SATURDAY & SUNDAY, ROSS DIS- 
TRIBUTING COMPANY, 78 SOUTH 
STATE, (P.O. Box 234). PRESTON ID 
83263. {208) 652-0830. FAX (208) 
852-0833. FAX {208) 852-0833, 

BNB654 



r 



WRITTEN EXAMS SUPEREASY. 

Memory aids from psychoiogist/erigi- 
neercutsludytime50%. Novice, Tech, 
Gen: $7 each. Advanced. Extra: $12 
each. Moneyback guarantee. Bahr, 



n 



Barter 'N' BLpy advertising must pertain to ham radio products or services. 

G Individual (noncommercial) 50C per word 

DCoiTtrnerclal .,.**..- + .♦♦,,...,,.,,. $1 ,50 per word 

Prepayment reqyired. Count only the iyords In the text Your address is 
free^ 73 cannot verify advertising claims and cannot be held responsible 
for claims made ijy the advertiser. Liabifity will be limited to making any 
necessary corrections in the nexi available issue. Please print dearly or 
type (double-spaced). 



No discounts or commissions are available. Copy mast be received in 
Peterborough by the first of the second month preceding the cover date. 
Wiake checks payable to 7J Magazine and send to: Donna DIRusso, Barter 
*N' Buy, Box 278, Forest Road, Hancock, NH 03449. 



J 



Dept 73-8. 1196 Citrus, Palmbay FL 
32905. BNB691 



ROSS $$$$ USED August SPE- 
CIALS: KENWOOD TS-530S $619.90, 
R-300 $189.90, T^599D & R-599D 
$509.90. ICOM IC-211 $389.90, IC- 
271 H $689.90, IC-246SSB $249.90, 
IC-255A $179.90. RM-2 AS IS $29,90. 
KAYPRO 10. 10 MEG, $999. 90, 
KAYPRCK2 $499.90, COLLINS KWM- 
3803 FILTERS NB.SP. $1995.90. ETO 
76A $1299.90, 374A $1795.90, 
ROBOT 400 $319.90. LOOKING FOR 
SOMETHING NOT LISTED?? CALL 
OR WRITE. WE HAVE OVER 235 
USED ITEMS In stock. MENTION AD. 
Prices cash, F.O.B. PRESTON, 
HOURS TUESDAY-FRIDAY 9:00 TO 
6:00, 9:00-2:00 P.M. MONDAYS. 
CLOSED SATURDAY & SUNDAY. 
ROSS DISTRIBUTING COMPANY, 78 
SOUTH STATE, P.O. BOX 234, PRE- 
STON ID 83263. (208) 852-0830. FAX 
(208) 852-0833. BNB709 



$50 PACKET DIGICOM > 64— A fan- 
tastic software based PACKET system 
Idr the Commodore 64. Order KIT #164 
for $49.95 or Assembly #154 lor 
$79.95, both include FREE DISC. Add 
$3.50 s/h. A&A Engineering, 2521 W. 
LaPalma, #K, Anaheim CA 92801. 
(714)952-21 14. MO or VIS A accepted. 

8NB732 



HAM TRADER YELLOW SHEETS. In 
our 28tri year. Buy, Swap, Sell ham 
radio gear. Published twice a month. 
Ads quickly circuiate. no long wait for 
results. Send business size SASE for 
sample copy. $13 for one year (24 is- 
sues). P.O.B. 2057, Glen Etiyn IL 
60138-2057 or P.O.B. 15142, Seattle 
WA98115. BNB741 



$$$$$ SUPER SAVINGS $$$$$ on 
electronic parts, components, sup< 
plies, and computer accessories. Send 
one dollar for 1-year subscription lo our 
40-page catalogs and their supple- 
ments. Get on our mailing list. BCD 
ELECTRO, PO Box 830119, Richard- 
son TX 75083 or call (214) 343-1770. 

BNB749 



WANTED: Ham EQuipment and other 
property. The Radio Ctub of Junior 
High Schooi 22 NYC, Inc., is a nonprof- 
it organization, granted 501(C)(3) 
status by the IRS, incorporated with 
the goal of using the theme of ham 
radio to further and enhance the edu- 
cation of youf^g people nationwide. 
Your property donation or financial 
support would be greatly appreciated 
and acknowledged with a receipt for 
your tax deductible contribution . Lat>or 
day and the new term are almost here. 
Do It, don't wait till the end of the year, 
make your decision to donate that 
equipment now. We depend on you. 
Please write us at; PO Box 1052, New 
York NY 10002. Round the clock Hot- 
line: (516) 674-4072. Thank you! 

aNB762 



INDIVIDUAL PHOTO FACT FOLD* 
ERS. #10 to #1400, $4.00. #1401 up. 
$6.00. Sam's books. $7.00. Postpaid. 
Allen Loeb. 414 Chestnut Lane, East 
Meadow NY 1 1 554. BNB766 

AVANTEK ATF10135 $12.00, 
MMlC^s, P.C. board. SASE: WA31AC, 
7148 Montague St.. Philadelphia PA 
19135. BNB771 

HAMLOG COMPUTER PROGRAM 

Full features. 17 modules. Auto-logs, 
7-band WAS/DXCC. Apple $19.95. 
IBM, CP/M, KAYPRO, TANDY, CR8 
$24.95. 73-KA1AWH. PB 2016, Pea- 
body MA 01 960. BNB775 

ELECTRON TUBES: All types & sizes. 
Transmitting Receiving, Mi- 
crowave ... Large inventory = same 
day shipping. Ask about our 3-500Z 
special. Daily Electronics. PO Oox 
5029 Compton, CA 90224. 800-346- 
6667. BNB792 

QUALITY OSL CARDS, RUBBER 
STAMPS, Envelopes and printed let- 
terhead. Send 45c postage or SASE for 
samples. Large selection a! attractive 
prices. Sandoltar Press, P.O. Box 
30726. Santa Barbara CA 93130, 

BNB812 

HUGE K1BV DX AWARDS DIRECTO- 
RY, complete rules for over 1015 cer- 
tificates. 102 countries, 230 pages. 
$15.50 postpaid. Ted Melinosky, 525 
Foster St,, South Windsor CT 06074- 
2936. BNB835 

100 QSL CARDS $8t Shipped post- 
paid. Free samples. Shell Printing, 
KD9KW. PO Box 50A. Rockton IL 
61072. BNB869 

THE NATIONAL HAM SHOPPER 
"'NHS.'^ Monthly buy, sell, trade publi- 
cation. Why keep that OLD RIG 
around? You could turn it into CASH$ 
or another rig you always wanted. Adds 
are quickly adverlisad and answered 
for fast results. As a NEW SUB- 
SCRIBER you can place one FREE 
ADD (with a 60 word limit). Add Rate: 
Noncommercial 0.25/word; Commer- 
cial 0,60/word. Subscription: $10.00/ 
year. $20/2 years. SEND TO: NHS, PO 
BOX 10738. ELMWOODCT06110. 

BNB665 

CURRY COMMUNICATIONS proudly 
introduces a complete line of easy to 
build kits for L,F. and 1750 meters. 
Please write for brochure. Curry Com* 
munications, 852 North Lima Street, 
BurbankCA 91505. BNB874 

WANTED: All types of Electron Tubes. 
Call toll free 1 {800)421 -9397 or 1 (61 2) 
429-9397. C & N Electronics, Harold 
Bramstedt, 6104 Egg Lake Road, 
Hugo MN 55038. BNB87a 

RIT KITS for most transceivers, $15. 
Info only, send SASE. Loren Wallan 
KA7AZM, 6323 S.W. tOOth, Tacoma 
WA 98499. BNe&65 



94 73 Amateur Radio • August, 1989 



QUANTITY DISCOUNTS ON TEK^ 
THONIX DUAL TRACE ffSSt SCOPES 
(DC-3500 MHz). Encell^nl condition, 
$60 ea (lots of 10— $30 @a). Also: 
HQwIeU-Packard Signal Generators 
V8-4 GigaHertz, excellent con di (ion, 
$50 ea (lots of 10 — $40 ea). Also; Vari- 
oys slgnaT gen a rata r^ 1-7 GigaHertz. 
$50 ea (bis of 10--$4O ea), f,Q.B. 
WWSB. PC Bq% 460, Bfookshtra TX 
77423, [71 3) 934-4659. aNB886 

DUST COVERS— Protect your valu- 
able Radio Gear, Custom made, beau- 
tifut fit. Send Make/dimensions. Most 
RadioSt $12,95, Catalog, $1 Dmosaur 
Covers. 173 Foster Road. Lake 
Bonkonkoma N Y 1 1 779. BNB888 

SUPER HAM PROJECTS & USE0 
GEAR LJSTSI Send SASE lo: 
WA4DSO, 3037 Audrey Dr.. Gastonia 
NC2B054. SNSa90 

SURPLUS CATALOG. 72 pages- $2- 
Sufplus, PO Box 276, Alburg VT 
05440. BNB891 

220 MHz AMP WANTED. MlfsTT EN- 
COMM 250 WATT MODEL ONLY. 
CONTACT WA9K12 at R.R. 4 SOX 
ISA. FLOWER IN 47944. OR GALL 
(31 7) 869-4073. BNBa92 

JARSFEST '89, BENSON NC Oct 1. 
JOHNSTON AMATEUR RADIO SOCI- 
ETY, PO BOX 1154. SMITHFIELD NC 
27577. BNB693 

BIRO ELEMENTS. WATTMETERS, 
DUMMY LOADS— Buy and SelL (609) 
227-5?69. Eagle, 100 Dearborn© Ave. 
Blackwood NJ 0B012. BNe694 

ANTIQUE RADIO TUBES— Unused, 
original boxes. "Loctals," battery 
types also. George Hoover, PO Box 
521 , Gouverneur NY 13642. BNBS95 

MOSLEV 75 METER 2*e(ement linear 
loaded beam— 82 FT elements- 36 FT 
boom— one of a kind prototype- works 
great, used 3 monthSn sold QTH must 
sell antennas— cost $2900. sell 
$1497_KK4WW, PO Box 1. Blacks^ 
burg VA 24063. (703) 382-4458. 

BNBa9€ 

FOR SALE-TEMPO 2020 Excelleril 
Condttion, has 11 melers plus New 
D104. $400 plus shipping. Call Gary 
(207) 773-4822. BN8e97 

SATELLITE TV VIDEOCIPHER II 
CHIPS Send SASE for Info. 3715 Mur- 
doch Ave. 109, Parkersburg WV 
26102. BNB89a 

TRANSMrrrWG tubes: Unused El 
MAC 4-250 and 2-1000 transmitling 
tubes. Make art offer! George Faster, 
29 Walcatt Valley Dr.» Hopkinton MA 
01748. BNBa99 

MAKE YOUR OWN REPEATERS Mo- 
torola Mi cor Radios 45 watt. 4 freq, 
136-150 MHz $80.00. Motorola Micor 



Radios 45 watt, 8 freq. 13S-150 MHz 
SI 20.00. Motorola Molracs Radios 25 
MHz $32.00. Micor Access Groups 4 
freq. Scan Head, spkr., mic. cable 
$75.00. Micor Access Groups 8 freq. 
Scan Head, spkr., mic, cable Si 00,00. 
GE Exec 11's Radio 45 watt^ 1 freq. 
138-150 MHz $100.00 with all acces- 
sofies S2(X).00. GE Exec 1 1 Radio 50 
watt, 42-50 MHz $100.00 with all ac- 
cessories $200.00. EM-2 DTMF mics 
with Micor, Mitreks. Syntor PJugs, hard 
wire changeable with schematic 
$20.00. DTMF Encoders with lite. 
Choice Of Plug Micor or Master II 
$30,00 each. LAMBDA Power Sup- 
plies LNS-P-12, 120 volts, 12 volt DC 
14 Amp $100,00. Wolfe Communica- 
tions. 1113 CentraJ Ave.. BiNings MT 
591 02. (406) 252-9220- BNB900 

KAM C-64 Does anyone know of any 
good software, all rtKXle for thts pair, 
other ihan "Kanterm." WB5JAP, 2109 
Samy Ln, Irving TX 75060. 8NB901 

SUPER HAM QTH St. Augustine FL. 
Anaslasia Island. Beautiful 2 Bedroom 
2 Bathroom house on {arge plot. V^ew 
IntercosiaL walk to Ocean beach. 
Backyard borders saltwater canal. All 
appliances including central air. Mtnl 
condition only 3 years old. Asking 
$89,500.00. (516) 271-5784 night 
(516) 367-8420 daytime ask for Fred 
(N2JCD). BNB902 

ICOM, KENWOOD & YAESU OWN- 
ERS: 8 Pole & 10 Pole Crystal Filters & 
monthly informative individual 
Newsletters! Our 10th year! Ask your- 
self these questions: Are you continu- 
ally being interfered with during 080? 
You can't seem to pull out a weak sig^ 
nal in the QRM? Yes, to either, puf- 
chase our SSB or CW filters. Send 0.45 
SASE for free catalog. International 
Radio & Computers, Inc., 751 SW 
Macedo Blvd., Port St. Lucie FL 34983. 
(407) 679-6868. BNB903 

QSLS & RUBBER STAMPS-TOP 
QUALITYI States, World Maps, USA, 
Key, Shuttle. Globe OSLs. Report 
Form Rubber Stamps. More! Samples 
$1 .00 [Refundable With Order], Ebbert 
Graphics D-7, Box 70, Westerville OH 
43081, BNB904 

CW IDENTIFIER: 7(X> Hz Sinewave. 
Accurate 10-Minute Timer, 9^12VDC. 
Instructions, Guaranteed. $79.95. 
OMR Oil Tools, Inc., 61^ Rex Drive. 
Daflas TX 75230-3429. (214) 891- 
0509^ BNB905 

m-Z90A PARTS LfSTSASe, C PRO 26 
Infantry Manpack Radio, compact. 6 
Meter FM, Recetver-Transmitter sec* 
tions, case, antenna, crystal, handsel: 
$22.50 apiece complete. $39.50/pair. 
Patrol Seismic Intrusion Device 
C^PSID") TRC*3: $42.50 apiece, 
Sl47.5Q(Se1 of four. Military-spec TS- 
352 Vohohm/Muiti meter, leads, InfBr- 
matJon: $12.50. Add $4,50/piece ship- 
ptng« $9 maximum. Baytronics, Box 
591 . Sandusky OH 44870. SNS906 




Number 41 on your Feedback card 



ROPA GA TION 



Jim Gray WtXU 
210 Chateau Circte 

Payson AZ $5541 

Late Summer Forecast 

August will be typical of the 
summer months, with moderate 
solar activity. Expect OX on 10 
meters, and around-th&<:lock DX 
on 20 meters. Twelve and 17 md- 
ters will be somewhere in be- 
tween. 

Forty meiers will provide DX 



Jim Gray WIXU 

*rom sunset to dawn, and 30 me- 
ters wril be a good nfghttime bend. 
Good daytime short skip will be 
available on all bands. 

A very active sun will cause ge- 
omagnetic field disturbances at 
ttmes, and there vinll be frequent 
solar flares. Check the daily 
charts for expected Good (G), Fair 
(F), and Poor (P) days. 

Day*to-day conditions follow 
below, as shown on the eaten- 
daf. 



EASTER 
























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73 Amateur Radio • August. 1989 95 



This is an Amateur 
Radio License 



TRANSFERABLE 



CALL SIQN 






?A 






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T>fiS iiCl^f^ (S aua/ECr to CONDftiOPCS or GniAJVt ON fkEV&VSS. SIDE 



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UNITIO STATES 01^ AMER5CA 

FEOERAl COMMUNlCATtOMS COWMfSStON 

GETTYSBURG. PA 17326 



commmoH 




This is an Amateur 
Television License 



NOT TRANSFERABLE 



TFCHJJICIAN 






1 



PPT ^ 



EC^Ei 



ifi 



TMlt DO^lie I* Suaj€Cf T^ '"CMTiONS Ot 3R«i7 Ofi ftE,[ER$€ »JD£ 



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UNITED ^ i A ; ES OF AMERICA 

FEDEflAt. COMMUNICATIONS COMMISSION 

GETTVS8URG PA 1(326 



COMHUNICATiOlin 

ccumntOH 




That's right, they are exactly the same. Your technician or higher class 
amateur radio license gives you the right to own and operate your own 

amateur television station. 



It's Easy.,„ 

If you can operate a 
video camera, you can 
operate the new AEA Model 
FSTV-430. TheFSTV-430 
transceiver connects to the 
video output of your camera 
and transmits and receives 
live or taped video. You can 
even use two cameras for 
studio-like operation from 
your shack. 



Fast Scan 
Television with the 
new FSTV-430 
from AEA gives 
you live, color 
television that 
rivals broadcast 
quality. In fact, the 
AEA Vestigial 
Sideband (VSB) 
technique is similar 
to that used by 
broadcasters. 



Inexpensive... And Fun.... 



The video camera or cam- 
corder you bought is the 
most expensive part of a fast 
scan television system. The 
AEA Model FSTV-430 is 
the only transceiver you 
need. Connect the camera, a 
430 MHz antenna, (an 
amplifier if you want 
stronger signals) and you're 
on the air. 




Think about it. You can 
share more than just conver- 
sation with your amateur 
friends. Show your friends 
the new transceiver you 
bought, that special antenna 
project you're working on, 
or just chew the fat. 

For more infonnation on 
the FSTV-430 and other 
exiting amateur 
television products, 
please contact 

Advanced 
Electronic 
AppIicationSjfnc. 

P.O.Box C-2 160 
Lynnwood, WA 98036 
206-775-7373 

AEA Retail S499.95 

Amateur Net $439.95 

y 119 



CIRCLE 6S ON READER SERVICE CAAD 



TWO OFAMEKCAS 

MOST POPULAR 
FM ST^IONS. 




No wonder Yaesu's FT-212R Series and 
FT-4700RH mobiles are so popular 

Not only are the features unique and 
plentiful the operation hassle-free. And 
the mounting options flexible. But also, 
each radio now features a built-in PL 
board, Plus^Wi choose the optional 
mic that best fits your operating and 
budget needs. 

FT'212R SERIES. MOBILES TH.AT 
DOUBLE AS ANSWERING MACHINES. 



Let the 2^meter FT^212R and 440-MHz 
FT'712R take messages while youYe away (with DVS-1 opt inn)! 45-watt output (35W 
on 440 MHz). Built-in PL encode/decode. 18 memories. Auto repeater shift Scan- 
ning routines. Offset tuning from any memory channel. Extended 
receive. Audible command verification. 
High/low^ power switch. Oversize amber 
display Choice of optional mic. More. 

FIMTOORH- DUAL-BAND PERFORMMCE 
REMOTE-HEAD DESIGN. 

Mount the FT4700RH almost any- 
v^hore— the'*brains"on your dash, visor, 
or door; the ''muscle'' under your seat- 50 
watts on 2 meters, 40 watts on 70 cm. Full 
erossband duplex. Simultaneous monitoring 
of each band, complete with independent 

squelch settings on the main and 

secondary bands. Built-in PL 

encode/decode. 9 memories (each 

band). Extended receive. Reverse repeater shift High/low^ 
}ower switch. Patch cord for remote mounting. Bright 
CD display Back! it controls. Choice of optional mic. 
More. 

Want more information? Call (800) 999-2070 toll- 
free. Or ask your dealer about Yaesu's FT-212R Series and 
_ . FT4700RH mobiles todav, Tlvo of Americans favorites. 

mi'^smiF •l M '^ ^KAESU USA 17210 Edwards Road. Cerritos, CA 90701 
mic. urMHis ^^^W (213 ) 404-2700. REPAIR SERVICE: (213) 404-4884. 
m miFnuto- — PARTS: ( 213 ) 404 4b47 

diaitr mic 







Prices and speeifitations subject to change without notice. PL is a registered trddemark of Moiorote, Int Specifi- 
cations guaranteed unly within amateur bands. 




f. 







> 



A 



. . - pacesef ter In AmaXeur Radio 



Affordable DX-ing! 



TS-140S 

HF transceiver with general 
coverage receiver. 

Compact, easy-to-use, full of oper- 
ating enhancements, and feature 
packed. These words describe the 
newTS-140S HF transceiver. Setting 
the pace once again, Kenwood intro- 
duces new innovations in the world 
of *' look-alike'* transce ivers ! 

• Covers all HF Amateur bands with 
100 W output. General coverage re- 
ceiver tunes from 50 kHz to 35 MHz. 

(Receiver specification 5 guaranteed from 

500 kH^ to 30 MHz.) Modifiable for HF 

MARS operation, (Permit required^ 

• AH modes butlt-in. LSB, USB, CW FM 

and AM. 

• Superior receiver dynamic range 

Kenwood DynaMix'" high sensitivity 
direct mixing system ensures true 102 
dB receiver dynamic range. 




• New Feature! Programmable band 
marker. Useful for staying within the 
limits of your ham license. For con- 
testers, program in the suggested 
frequencies to prevent QRM to non- 
participants. 

• Famous Kenwood interference 
reducing circuits. IF shift, dual noise 
blankers, RIT, RF attenuator, selectable 
AGCand FM squelch. 



• M, CH/VFO CH sub-dial. 10 kHz step 

tuning for quick QSY at VFO mode, and 
UP/DOWN memory channel for easy 
operation. 

• Selectable full (QSK) or semi 
brealc-in CW. 

• 31 memory channels. Store fre- 
quency, mode and CW wide/narrow 
selection. Split frequencies may be 
stored in 10 channels for repeater 
operation. 

• RF power output control. 

• AMTOR/PACKET compatible! 

• Built-in VOX circuit 

• MC-43S UP/ DOWN mic. included. 
Optional Accessories: 

• AT-130 compact antenna tuner • AT-250 auto- 
malic antenna tLjner • HS-5/HS-6/HS-7 head- 
phones • IF-232C/IF-10C computer interface 

• MA-5/VP-1 HF mobfle antenna {5 bands) 

• MB-430 mobile bracket • MC'43S extra 
UP/DOWN hand mic * MC-55 {8-pin) goose neck 
mobile mic* iyiC-60A/MC"80/MC-85 desk mics. 

• PG-2S extra DC cable • PS-430 power supply 

• SP-41 /SP-50B mobile speakers • SP-430 
external speaker* TL-922A 2 kW PEP linear 
amplifier (not for CW QSK) • TU-8 CTCSS tone unit 
•YG-455C-1 500 Hz deluxe CW filter, YK-455C-1 
New 500 H2CW filler. 



ftlT"^ LP SHIt^T 



POWEH 



H TBa Wfl w 



I u J n n n 

t % L U Lh U 






II it 



ON MP MsiJH f-tjOtJK 





TS-680S 



All-mode multi-bander 

• 6m (50^54 MHz) 10 W output plus all HF 
Amateur bands (100 W output). 

• Extended 6m receiver frequency range 45 MHz 
to 60 MHz. Specs, guaranteed from 50 to 54 MHz, 

• Same functions of ttie TS-140S except optional 
VOX (VOX-4 required for VOX operatmn), 

• Preamplifier ioi 6 and 10 meter band, 



' ■ 4 




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COfOplete service waouafs areavailabfe toraii Kenwood 
Transceiver sand most accessories. Specifications, features. 
3nd pffQe§ are $uhj&a io cha nge with ou! na t ice or o bfiga tio n . 

KENWOOD 

KENWOOD U.S.A. CORPORATION 

2201 E. DominguezSt., Long Beach, CA 90810 
RO. Box 22745, Long Beach. CA 90801-5745